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"Evaluation of a Low-Disturbance Rolling Tine
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presented by

Benjamin B. Bailey

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6/01 c:/ClRC/DateDue.p65—p.15

FIELD PERFORMANCE OF A LOW-DISTURBANCE ROLLING—TINE SLURRY
INJECTOR

By

Benjamin Bowman Bailey

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Agricultural Engineering

2003

ABSTRACT

FIELD PERFORMANCE OF A LOW-DISTURBANCE ROLLING-TINE SLURRY
INJECTOR

By

Benjamin Bowman Bailey

A low-disturbance rolling-tine manure slurry injector was evaluated for effects on
soil infiltration, residue cover, slurry placement uniformity, and soil electrical
conductivity. Initial water infiltration rates were found to be greater for more
aggressively tilled plots. Aggressively tilled plots had a lower residue cover. Soil
electrical conductivity (EC) and phosphorous (P) concentrations were measured in
untilled, lightly tilled and aggressively tilled plots with manure applied at 49100 L ha'l
(5,250 gpa). P concentrations were analyzed with and without soil EC as a covariate. P
concentrations in the 0-7.6 cm (0-3 in) layer were greatest at the points of greatest soil
disturbance. Using soil EC as a covariate in the analysis of soil P improved the accuracy
of the analysis. Soil EC values were not affected by tillage at the 91 cm (3 ft) depth. Soil
EC levels were increased by tillage at the 30 cm (1 ft) depth, with light and no tillage

showing the largest increase.

ACKNOWLEDGEMENTS

I would like to thank Al Buckrell from Aerway and Richard Wolthius from MSU
for helping with the hitch and hose plumbing to make the equipment field worthy. Thank
you to Tim Godfrey of Godfrey Farms for running the Veris EC soil sampler. Thank you
to Barry and Kevin from university farms for their help and support with the field work.
I would like to thank Brian Graf also of university farms for helping with the soil
processing. I thank Brandon Glaza for building the rainfall simulator and double ring
infiltrometer and for showing me the osage orange tree. I would like to thank Timothy
Krause for helping with the rain fall simulator.

I would like to thank the members of my committee. I would like to thank Dr
Carrie Laboski for her help and direction with the soil sampling. I would like to thank
Dr. Sasha Kravchenko for her help and patience with the statistical analysis. I would like
to thank Dr. William Northcott for his help with the infiltrometer, rainfall simulator, and
Arcview. I would like to thank Dr. Tim Harrigan for his patience, good humor, and
funding (research assistantship) that has made it all possible.

I would like to thank my wife Christy and my son Abraham for letting a dreamer
go to graduate school. And I thank “Him who has created you from the beginning, and is
preserving you from day to day, by lending you breath, that ye may live and move and do

according to your own will, and even supporting you from one moment to another”.

111

TABLE OF CONTENTS

LIST OF TABLES ................................................................................... vi
LIST OF FIGURES .................................................................................. ix
CHAPTER 1. INTRODUCTION ................................................................... l
1.1 Justification ............................................................................... 1
1.1.1 Benefits of Manure Application .................................................. 2

1.1.2 Risks of Manure Application .................................................... 2

1.2 Literature review ......................................................................... 6
1.2.1 Precision Application ........................................................ 6

1.2.2 Slurry Incorporation Methods ................................................ 8

1.2.2.1 Environmental Benefits ........................................ 12

1.2.2.2 Crop Response ................................................... 14

1.3 Objectives .............................................................................. 15
CHAPTER 2. METHODS AND MATERIALS ................................................ 16
2.1 Rolling-tine harrow ..................................................................... 16

2.2 Tillage with the rolling-tine harrow, no manure ................................... 18

2.2.1 Initial Infiltration Rate ..................................................... 18

2.2.2 Residue Cover ............................................................... 19

2.3 Tillage with the rolling-tine harrow, with manure ................................. 20

2.3.1 Surface Manure Coverage .................................................. 20

2.3.2 Bulk Density ................................................................. 21

2.3.3 Volume and surface area of tilled soil ................................... 21

iv

2.3.4 Nutrient Placement Uniformity ........................................... 22

2.3.5 Electrical Conductivity .................................................... 24

CHAPTER 3. RESULTS AND DISCUSSION ................................................. 27
3.1 Tillage with the rolling-tine harrow, no manure ................................... 27

3.1.1 Initial Infiltration Rate ..................................................... 27

3.1.2 Residue Cover ............................................................... 28

3.2 Tillage with the rolling-tine harrow, with manure ................................. 28
3.2.1 Surface Manure Coverage .................................................. 28

3.2.2 Bulk Density ................................................................. 29

3.2.3 Volume and surface area of tilled soil ................................... 30

3.2.4 Nutrient Placement Uniformity ........................................... 31

3.2.5 Analysis of soil P with soil EC as covariate ............................ 33

3.2.6 Electrical Conductivity .................................................... 37

CHAPTER 4. CONCLUSIONS ................................................................... 40
CHAPTER 5. RECOMMENDATIONS .......................................................... 42
REFERENCES ...................................................................................... 44
APENDIX A ......................................................................................... 48
APENDIX B ......................................................................................... 61
APENDD( C ......................................................................................... 65

LIST OF TABLES
Table 1: Liquid Dairy Manure Analysis ......................................................... 17
Table 2: Ten minute water infiltration rates for a loam soil with a rolling-tine harrow ...27

Table 3: Wheat straw residue cover following tillage with a rolling-tine

harrow on a loam soil ..................................................................... 28
Table 4: Soil bulk density (g/cm3) following light and aggressive tillage .................... 29
Table 5: Volume and surface area of tilled soil .................................................. 30

Table 6: Bray l-P at 3 depths and 3 positions relative to tine penetration for 4
individual tillage and manure treatments .............................................. 31

Table 7: Bray l-P means for the interaction of depth and position for all treatments ...... 32
Table 8: Bray l-P means for the interaction of depth and treatment ........................ 33

Table 9: Mean Bray l-P concentrations at difi'erent tine penetration positions at 0-7.6 cm
(0-3 in) obtained from the data analyses with and without soil EC ................ 35

Table 10: Relationships between soil P concentrations and soil EC at different
manure-tillage treatments at 0-7.6 cm (0-3 in) ...................................... 35

Table 11. Mean soil P concentrations at different treatments at O-7.6 cm (0-3 in)
obtained from the data analyses with and without EC as a covariate. Standard

errors for treatment means are shown in parenthesis ............................... 36
Table12: Soil EC (mS/m) 30 cm (1 ft) following tillage treatments ......................... 37
Table 13: Independent 0-30 cm (0-12 in) soil parameter Pearson correlation

coefficients and p value matrix ........................................................ 39
Table 14: AN OVA of stepwise regression parameter estimates of soil EC ................. 39
Table A1: Ten Minute soil infiltration rates ..................................................... 48
Table A2: Percent residue cover ................................................................... 48
Table A3: Surface manure coverage ............................................................... 48

Table A4: Soil bulk density (g/cm3) south and south ends of plots
after slurry application (21 August 2002) ............................................ 49

vi

Table A5: Soil P levels at 3 depths and 3 positions relative to tillage
for no tillage and no manure ........................................................... 49

Table A6: Soil P levels at 3 depths and 3 positions relative to tillage
for no tillage with manure ............................................................. 49

Table A7: Soil P levels at 3 depths and 3 positions relative to tillage
for light tillage with manure ........................................................... 50

Table A8: Soil P levels at 3 depths and 3 positions relative to tillage
for aggressive tillage with manure .................................................... 50

Table A9: Interpolated pre-application soil EC (mS/m) to 30 cm (1 fl) depth by

plot number ............................................................................. 51

Table A10: Pre-application soil EC (mS/m) to 91 cm (3 ft) depth

(interpolated values) by plot number ................................................. 52
Table A1 1: 1 day after application interpolated soil EC(mS/m)

to 30 cm (1 ft) depth by plot number ............................................. 53
Table A12: 1 day after application interpolated soil EC (mS/m)

to 91 cm (3 ft) depth by plot number ............................................. 54
Table A13: 1 week after application interpolated soil EC(mS/m)

to 30 cm (1 ft) depth by plot number .............................................. 55
Table A14: 1 week after application interpolated soil EC (mS/m)

to 91 cm (3 ft) depth by plot number .............................................. 56
Table A15: OM, P, and K of multiple depth soil cores taken at flags ........................ 57
Table A16: Mg, Ca, and pH of multiple depth soil cores taken at flags .................... 57
Table A17: Clay, sand and silt of multiple depth soil cores taken at flags .................. 58
Table A18: CBC and EC of multiple depth soil cores taken at flags ......................... 58
Table A19: Soil bulk density (g/cm3) at flags before slurry

application (15 August 2002) ........................................................ 59
Table A20: Gravimetric water content at flags before

application (14 August 2002) ........................................................ 59
Table A21: Gravimetric water content (g/ g) at flags after

application (26 August 2002) ........................................................ 6O

vii

Table Bl: Ten minute infiltration rate AN OVA ........................................ 61

Table BZ: Residue cover ANOVA ................................................................ 61
Table B3: Surface manure coverage ANOVA .................................................... 61
Table B4: ANOVA table for Bulk Density as a function of treatment and depth... . . . . ...61
Table B5: Phosphorous application uniformity AN OVA ...................................... 62

Table B6: Analysis of covariance table for phosphorus concentration as a function of
treatment and tine position with soil EC as a covariate ........................... 62

Table B7: AN OVA table for phosphorus concentration as a function of treatment

and tine position ......................................................................... 62
Table B8: Pre-application soil EC at 91 cm (3 ft) depth ANOVA ............................ 63
Table B9: 1 day after application soil EC at 91 cm (3 fl) depth ANOVA ................... 63
Table B10: 1 week after application soil EC at 91 cm (3 ft) depth ANOVA ............... 63
Table Bl 1: Pre-application soil EC at 30 cm depth (1 fl) ANOVA .......................... 63
Table BIZ: 1 day afier application soil EC at 30 cm depth (1 ft) ANOVA .................. 63
Table B13: 1 week after application soil EC at 30 cm depth (1 fl) AN OVA ............... 63

viii

LIST OF FIGURES

Figure 1: Position of sampling for phosphorous relative to tillage ............................ 23
Figure 2: Soil P (ppm) verses 1 ft pre-application soil EC (mS/m) ........................... 35
Figure 3: Pre-application 1 foot interpolated EC ................................................ 38
Figure A1: Interpolated Pre-application soil EC (mS/m) to 30 cm (1 fl) depth ............. 51
Figure A2: Interpolated pre-application soil EC (mS/m) to 91 cm (3 it) depth. . . . . . . . .....52
Figure A3: 1 day after application interpolated soil EC(mS/m) to 30 cm (1 ft) depth. . ...53
Figure A4: 1 day afier application interpolated soil EC (mS/m) to 91 cm (3 ft) depth. ...54
Figure A5: 1 week after application interpolated soil EC(mS/m) to 30 cm (1 fi) depth...55
Figure A6: 1 week after application interpolated soil EC (mS/m) to 91 cm (3 ft) depth..56
Figure C1: Shatter tine helical mount configuration for two sets of shatter tines

(courtesy of AerwayTM) ............................................................... 65
Figure C2: Rear and side views of rolling tine harrow (courtesy of AerwayTM) ............ 65
Figure C3: Top and side of 10 foot rolling tine harrow. (courtesy of Aerway“) .......... 66
Figure C4: AerwayTM rolling tine harrow manure injector. . . . .....66
Figure C5: AerwayTM in use on experimental plots ............................................. 67
Figure C6: Inside the AerwayTM grinder and distribution manifold ........................... 67
Figure C7: AerwayTM distribution nozzles with outlet shut-offs closed ...................... 67
Figure C8: Valve and pump configuration on Nuhn"'M tank ................................... 68
Figure C9: Hitch on NuhnTM tank ................................................................. 68
Figure C10: The double ring infiltrometer ....................................................... 69
Figure C11: The Veris® 3100 ..................................................................... 69
Figure C12: AerwayTM light tillage void cavities (excavation normal to travel) ............ 70

ix

Figure C13: AerwayTM light tillage void cavities, top view
(excavation normal to travel) ....................................................... 70

Figure C14: AerwayTM aggressive tillage void cavities, top view
(excavation normal to travel) ....................................................... 71

Figure C15: AerwayTM aggressive tillage void cavities, side view

(excavation normal to travel) ....................................................... 71
Figure C16: AerwayTM light tillage void cavity pattern ....................................... 72
Figure C17: AerwayTM aggressive tillage void cavity pattern ................................. 72
Figure C18: AerwayTM aggressive tillage 3-D void cavities model .......................... 73
Figure C19: AerwayTM light tillage 3-D void cavities model .................................. 73
Figure C20: AerwayTM no tillage surface manure coverage with tire track ................. 74

CHAPTER 1.

1. INTRODUCTION
1.1 Justification

Since the adoption of the 1972 Water Pollution Control Act, billions of dollars
have been spent to “restore and maintain the chemical, physical, and biological integrity
of the Nation’s waters” (Novotny and Olem, 1994). Initially, efforts were focused on
collection and treatment of point source pollution. Point source pollution includes
municipal, industrial, and some agricultural wastewaters. Point source pollution
legislation made pollution discharge improvements mandatory. Overall, the programs
targeting the effects of point source pollution were successful. However, point source
pollution is only part of the problem. Non-point source pollution (NPSP) is detrimental
to the integrity of the nations waters and land. NPSP varies with time, space, geography,
weather and land management. Land management practices are often used to prevent
NPSP.

The 1987 Water Quality Act was passed to prevent NPSP by voluntary
improvement of land management practices. Specifically, section 319 required states to
assess NPSP and develop Best Management Practices (BMP). The goal of a BMP is to
prevent loss of pollutants to the environment. A BMP is developed with the goal of not
exceeding the assimilative capacity for a given land or water body. The assimilative
capacity is the concentration at which the pollutant begins to significantly alter the
integrity of a land or water mass. Areas where land use is expected to significantly

contribute to NPSP are targeted for BMP implementation. These areas include

construction sites, mining areas, military grounds, silvicultural lands and agricultural
lands (Novotny and Olem, 1994). Applying manure slurry to agricultural land is a
practice of particular interest for NPSP. There are benefits and risks of applying manure
to soil.

1.1.1 Benefits of Manure Application

Land application of manure is an established practice used to dispose of animal
waste and amend soils. Manure can improve physical and chemical properties of soil.
Mathers and Stewert (1984) reported that manure application increased soil organic
matter, decreased bulk density and increased hydraulic conductivity. Wilkins and
Rasmussen (1993) reported that adding manure to soil reduced the draft of tillage tools.
Manure increases nitrogen, phosphorous and potassium concentrations in the soil
(Motavalli et a1 1985). Land application of slurry is an acceptable practice because of the
high assimilative capacity of soil.

1.1.2 Risks of Manure Application

The risks of manure application are:

1. Nutrients can be lost to air or water where they act as pollutants.

2. The application rate may not match crop needs.

Consider surface applied liquid manure with organic and inorganic nutrients.
Availability of nutrients from manure to crops may be highly variable depending on
interactions between manure and soil (Schell and Alder, 1997). Soluble inorganic
nutrients are distributed through the soil profile as liquid manure infiltrates the soil.

Soluble nutrients are available for crop use. Soil biota break down organic nutrients and

make the nutrients available to crops. Nutrients distributed through the soil by infiltration
may or may not meet the crop needs due either to availability or distribution.

Manure nitrogen consists of inorganic and organic nitrogen. Organic nitrogen is
not available to the crop until it is mineralized by soil biota. Nitrogen mineralization
converts organic nitrogen to ammonium (NI-14+). In this form nitrogen is available for
crop use. Ammonium is not very mobile as it may be held in the soil cation exchange.
Additionally, NIL;+ can undergo immobilization or nitrification. Immobilization occurs
when soil biota consume NH] and return it to an organic form. Nitrification converts
ammonium (NH4I) to nitrite (N 02') to nitrate (NOg'). Nitrate is also available for plant
uptake. Under anaerobic conditions NO3' can undergo denitrification whereby N2 is
released to the atmosphere. N02' and N03' are easily dissolved in water and, therefore,
are highly mobile. These dissolved pollutants are transferred by runoff and infiltration.
Nitrogen leached to ground water can lead to high subsoil N03' concentrations (Mathers
and Stewart, 1984; Chen and Tessier, 2001). Excess leached NO3' in ground water used
for drinking is a health risk.

Methemoglobinemia is caused when nitrates react with hemoglobin and impair
oxygen transport in blood (Humenik et al., 1982a). Surface waters receiving runoff
containing inorganic nitrogen are susceptible to increased aquatic plant growth and,
subsequent eutrophication.

Inorganic phosphorous (P) added to soil is fixed and held by a number of
processes. Phosphorous that infiltrates into the soil is easily fixed by sorption to clays
(aluminum and iron oxides). Phosphorous becomes available for plant uptake as it

desorbs from clay. Phosphorous may also be precipitated by binding with calcium. The

effects of precipitation can be reversed by dissolution. Immobilization of soil solution P
occurs when it is consumed by soil biota and held as organic P. Organic P can be
mineralized and release inorganic P for plant uptake. Phosphorous fixation and release
may occur simultaneously over time at different rates. Phosphorous build up is a
problem when P is applied at rates that exceed removal (Motavalli et al., 1985).
Phosphorous may also be lost from the soil through leaching and surface water runoff.
Runoff can remove P fixed to soil particles in sediment. The sediment accumulates in
lakes and streams. The phosphorus is released over time and perpetuates eutrophication.
Phosphorous leaching generally occurs in sandy soils with excessively high soil test
levels.

Poor infiltration of manure into soil may result in non-uniform distribution of
nutrients and nutrient loss. Overland flow and pooling are more likely to occur when the
liquid manure is slow to infiltrate into the soil profile. Pooling of nutrients in lower areas
of the field causes non-uniform distribution. Volatilization of NIL,+ to NH3 occurs when
manure is lefi exposed to air and NH3 dissipates into the atmosphere. Soil nitrogen is
decreased and odors increased by ammonia volatilization. Nitrogen losses from
volatilization vary greatly with the manure applied and the atmospheric and soil
conditions (Jokela and Cote, 1994). As much as 80 percent of manure nitrogen may be
lost to volatilization when manure is not incorporated (Jokela and Cote, 1994; Humenik
et al 1982a).

The application method determines manure distribution within the soil profile.

Surface applications result in nutrient stratification where greater concentration of

nutrients are near the soil surface. Large nutrient concentration in the surface soil present
a higher risk of nutrient loss to the environment.

Tillage can be used to incorporate manure into the soil. Incorporating slurry into
the soil increases the soil/slurry interface so soil biota can break down organic nutrients.
Tillage also places the nutrients in the root zone where they can be used. Tillage can
stimulate nitrification and increase soil temperature (Cavigelli etal., 1998). Aggressive
tillage lifts, fractures, and alters the soil structure. Increased soil disturbance increases
permeability, surface water storage capability and reduces runoff volume. Dunn and
Phillips (1991) compared no-till and conventional tillage infiltration rates using a double
ring infiltrometer. Conventional tillage infiltration rates were greater than no-till
infiltration rates.

Incorporating slurry into the soil with tillage brings additional challenges. Tillage
disturbs the soil structure making it susceptible to erosion. The most predominant
pollutant in surface waters is eroded soil sediments. Sediment can change water column
depth, temperature and habitat for aquatic life. Limiting tillage can reduce erosion by 60
to 99 percent by preserving residue cover (Humenik et al., 1982b). Aggressive tillage
can reduce the soil residue cover and increase the risk of erosion. Residue can absorb
some of the kinetic energy of wind and rain before it reaches the soil particles. Many
studies comparing no-till and minimal tillage systems with conventional tillage showed
that reduced tillage yielded less runoff sediment and volume, but the runoff from no-till
fields had increased nutrient dissolved concentrations (Humenik et al., 1982b). The
greater concentrations were caused by more nutrients remaining near the surface when

there was little or no incorporation of nutrients.

Implementing BMPs that control placement and retention of nutrients to meet
crop needs can reduce the risk of pollution. These practices include precision application
and slurry incorporation. Precision application is used to distribute slurry nutrients to
meet crop needs on a field scale. Tillage helps to retain nutrients in the root zone
thereby reducing the risk of nutrient loss to the environment. At the same time tillage can
increase the risk of erosion. Finding an appropriate method to unifome distribute and
retain nutrients in soil may require new application methods. There is a need to evaluate
the ability of new manure slurry injection tools to place the slurry uniformly throughout
the soil profile and prevent overland flow.

1.2 Literature Review
1.2.1 Precision Application

Precision agriculture allows producers to track slurry application and match
application rates with crop needs. An aim of precision agriculture is to manage
variability to enhance economic return and diminish environmental impacts (Morgan et
al., 1997). Geographic referencing of agricultural data is done with a Global Positioning
System (GPS). Site-specific information such as soil nutrients are geo-referenced with a
GPS and stored, managed and displayed using a Geographical Information System (GIS).
GIS software allows spatial analysis of geo-referenced information.

Variable rate application (VRA) of manure allows application of slurry to match
crop needs. There is a need to use precision agriculture for animal waste application
(Fleming et al., 2001). The challenges of slurry VRA include configuring equipment for
uniform application, real time measurement of soil and manure nutrients and variable rate

control.

Lague (1991) evaluated the application uniformity of a manure injection system.
Due to the difficulty in evaluating the subsurface application uniformity, the experiment
was performed above ground using collection pans. The length distribution proved to be
highly variable due to the hydraulic head loss as the tank emptied. Of the four injectors
on the distribution manifold, the two in the center always injected more manure. Thus,
equipment should be configured to distribute slurry uniformly for the width and length of
application.

Sensor based systems use real-time sensors for VRA feedback control (Morgan et
al., 1997). An example of an electronic soil sensor is the VerisTM electrical conductivity
(EC) cart. Soil EC can be used to predict soil chemical and physical properties. Ehrhardt
et a1 (2001) found that EC can be used to predict draft. Kravchenko et al. (2002) created
soil drainage maps using soil sampling and found that geo-referenced topographical and
EC data could be used to increase map accuracy. Johnson et al., (2001) classified soil on
a field scale basis using VerisTM EC values. Johnson et al (2001) reported correlations
between EC and other soil properties such that EC could be used as a predictor of field
soil properties. Electrical conductivity effectively predicted soils of varying soil texture,
moisture, bulk density (BD) , phosphorous (P), pH, cation exchange capacity (CBC) and
organic matter (OM; Johnson et al., 2001). Measurement of EC using VerisTM allows
large areas to be sampled quickly and inexpensively. These measurements may be used
to predict soil nutrient content and manure application rates changed in real time to
provide suitable precision application control.

Variable rate application of manure has been limited. Precision application

require precision metering and control. The application rate is a function of the slurry

flow rate, slurry nutrients, soil nutrients, crop needs and the speed of the implement.
Glancey et al., (1997) developed a solid manure box spreader which was equipped with
two screw conveyors to deliver manure to rear-mounted spinning plates. The screws
were driven by a hydrostatic motor. Strain gauges were attached to the axles and hitch to
determine the mass flow rate of the manure. The averaged strain gauge values were used
to reduce noise from bumpy off road conditions. An onboard ultrasonic speed sensor and
DGPS system were used to measure ground speed. The mass flow rate and ground speed
were used to control the hydrostatic motor on the conveyor. The system was capable of
VRA fi'om 2,300 to 11,400 kg /ha (2050 to 10180 lb/acre).

Chenard et a1. (1992) designed a 28.2 meter wide, hose fed, liquid manure
applicator. Two-stage flow control yielded precision control across the width of
application. Precision liquid manure application requires suitable and adaptive control.
The sensors and controls must also respond quickly to avoid spills. Munack etal., (2001)
developed adaptive predictive control for liquid manure. They used a magnetic inductive
flow meter which measured the travel time difference in magnetic pulses. The signal
from their magnetic inductive flow meter suffered from lags and delays which greatly
reduced the controller stability margin. The controller was improved with a Kalman filter
and a Smith Predictor. These improvements increased the speed and stability of the
controller for adequate precision control.

1.2.2 Slurry Incorporation Methods
When manure slurry is left on the soil surface nutrients can be lost to
volatilization and runoff or redistributed by overland flow. Slurry incorporation creates

soil voids to hold slurry in place after application and mix slurry with soil for increased

soil/slurry interface. Nutrients are available for crop use because they are held in the root
zone by the soil. Finding the appropriate amount of tillage is a challenge. Insufficient
tillage can result in inadequate slurry incorporation. But increased incorporation of slurry
with tillage can result in increased soil erosion. The purpose of the tillage is to
incorporate the slurry into the soil by disturbing the soil, injecting the slurry and in some
cases covering the slurry.

Disturbing the soil creates a void to receive the manure. Methods used are knife
or chisel, concave disk coulter, s-tine cultivator, sweep, aerator and the combination of
shank and coulter (J okela and Cote, 1994; Chen et al., 2001; Schell and Alder, 1997). A
knife injector opens a deep, narrow cavity in the soil. A concave disk injector has two
opposing disks that cover manure that has been applied on undisturbed soil. A coulter is
used to cut through crop residue. It is also suitable for opening grassland soil with low
disturbance. An s-tine cultivator is similar to a knife. The difference is that the s-tine has
small winged tips. This allows for greater soil disturbance at a more shallow depth
resulting is less required draft than with a knife (Negi et a1 1978). Sweep type injectors
have even larger wings than s-tines. Sweep injectors result in a more horizontal
distribution compared with concentrated vertical bands resulting from knife injection. A
rolling-tine harrow perforates the soil making voids for the manure to flow into. It is
suitable for grassland due to low disturbance and a reduced banding effect.

An injector draft requirement is the sum of the soil cutting forces and the
frictional forces on the tool (Huijsmans etal., 1998). The soil fiictional forces are a
function of soil conditions and the surface area of the tool. Soil cutting for manure

injection is accomplished horizontally (wing and sweep tools) and vertically (disc or

knife type tools). Koolen and Kuipers (1983) and Chen and Tessier, (2001) considered a
winged tool to be a two dimensional plane separating a soil beam from the furrow
bottom. The separation resulted in a short-lived cavity that was filled by the soil beam.

Disc and knife tools simply open a furrow. The soil cutting forces are a function
of soil conditions, the depth of injection and the effective cross-sectional area being
moved through the soil. The effective cross-sectional area is dependent on the rake angle
for wing and sweep tools. Reducing the depth or the cross-sectional area reduces the
draft but also reduces the manure void volume. Reduced power requirements are
achieved for a given application rate with shallow wing or sweep type injectors. Sweep
and wing injectors increase the allowable application rate at shallow depths by providing
sufficient voids to receive manure (Negi et al., 1978).

An objective of manure injection is to cover the manure with soil or place the
manure below the soil surface. Wing and sweep manure injection implements are
designed to allow the disturbed soil to fall down on top of the injected manure. In some
cases cover disks are used to ensure that injected manure is well covered. Insufficient
coverage occurs two ways, “overflow manure” and “in-furrow manure” (Chen and
Tessier, 2001). “Overflow manure” results when the liquid manure flow exceeds the
injection capacity of the tool (Chen and Tessier, 2001). “In-furrow manure” results from
a tool soil configuration with insufficient backfill to cover the manure in the furrow.
(Chen and Tessier, 2001). For example, backfill will inevitably occur with a winged tine
in sandy soil. However, backfill is not likely to occur with a coulter in clay or grass.
Pooling occurs when the volume of the manure exceeds the volume of the cavity formed

to receive it. Pooling is undesirable because of increased volatilization and nmoff risk.

10

Pooling may be reduced by increasing the injection depth or decreasing the application
rate (Chen et al., 2001).

Negi et al. (1978) evaluated cover performance and application uniformity of a
sweep tine manure injector prototype using empirical excavation. The prototype was
used to inject manure at 5 application rates. Twenty-four hours after injection, 30 cm (12
in) sections of the disturbed profile were excavated and measured. The depth of the
cover, depth of injection and the depth of the slurry soil mixture were measured. The
measured placement and uniformity were compared with the intended application
distribution. In this manner the effectiveness of the application was measured. Wide
injectors at shallow depths were observed to minimize draft while sufficiently
distributing and covering slurry for agronomic requirements

Aeration tillage tools perforate the soil creating voids in the soil surface for
manure placement. One such tool is the AerwayTM Sub-surface Deposition (SSD) Slurry
Manure Applicator (Appendix C, Figures C2-C5). The AerwayTM uses ground-driven
tines on a rolling shaft to perforate the soil surface requiring less power and resulting in
less soil disturbance than traditional injectors (Bittrnan et al., 2000). The shatter tines are
20 cm (8 in) long and mounted with a small tilt on two 8.9 cm (3.5 in) diameter shafts
(Appendix C, Figure C2). Figure Cl shows the shatter tine helical mount configuration
for two sets of shatter tines. A set of tines consists of four tines fixed perpendicular to the
rotating gang shaft. Sequential soil penetration is accomplished with helical mounting of
tines. Each adjacent row of tines is mounted 22.5 degrees ahead of the last row along the
shaft. The rolling-tine shaft gangs pivot with respect to the flame fiom zero to ten

degrees (zero being normal to direction of travel) in two and one half degree increments

ll

(Appendix C, Figure C3). When the gangs are set at zero degrees the tines roll parallel to
the direction of travel and disturb little soil (Appendix C, Figure C16). The ten degree
tine gang angle setting results in more aggressive tillage (Appendix C, Figure C17).
Manure injection nozzles are mounted behind each set of tines. The nozzles are
connected to a distribution manifold which chops and distributes manure to the nozzles.

At the zero degree gang angle setting the tines made voids in the soil that were 19
cm (7.5 in) long, 2.25 cm (0.89 in) wide and up to 11.5 cm (4.5 in) deep (Fuchs and
Zumwinkle, 2002). The void capacity was 0.14 L (0.036 gallons). The tool made about
72,600 holes per acre resulting in an overall void capacity of 24,000 Lha" (2,600 gpa).
1.2.2.1 Environmental Benefits

Manure incorporation reduces nutrient loss in sediment, runoff, and by
volatilization. Pollutants such as phosphorous which are bound to soil particles and
transported with sediment can be controlled by limiting tillage.

Placing manure under the soil can reduce concentrations of nutrients in runoff and
leachate. Runoff characteristics of agricultural practices are often compared using a
rainfall simulator. A simulator is used to create comparable hydrologic events to
generate runoff from test plots. Thompson et al (2001) used a rainfall simulator to
evaluate the effect of raindrop energy on sediment load and soluble chemical transport.
Sediment loss, soluble chemical leaching and soluble chemical in runoff were found to be
functions of raindrop energy. Ross et al. (1979) treated Bluegrass sod and tilled soil (silt
loam texture) with surface applied manure and spring tooth bar injected manure at two
depths. Runoff was collected from simulated rainfall generated by a sprinkler irrigation

system. The chemical oxygen demand (COD), total solids, pH, dissolved oxygen, and

12

fecal coliforrn of runoff were measured. Manure injection was found to substantially
reduce pollutants in runoff. The first 100 L (26 gallons) of runoff from the surface
applied plots had COD 17 times greater than the runoff from injected plots.

Fuchs and Zumwinkle (2002) used a rainfall simulator to collect runoff from
alfalfa plots treated with a broadcast manure with AerwayTM tillage, no manure with
AerwayTM tillage, manure without tillage and no tillage or manure. The tool was
configured so that manure was applied ahead of the rolling-tines. They measured runoff
for total solids, particulate phosphorous, soluble phosphorous, bioavailable phosphorous,
total phosphorous, BOD and COD. The AerwayTM tillage reduced the runoff flow rate.
However the total volume of runoff and concentration of pollutants in runoff were not
reduced.

Schell and Alder (1997) investigated liquid manure in reduced tillage cropping
systems. With the cooperation of producers, they incorporated manure into reduced
tillage cropland. After measuring nitrate movement they concluded that the risk of nitrate
leaching into ground water was not greater by applying manure compared to inorganic
fertilizers using similar nutrient levels.

When manure is left exposed to the air, nitrogen is lost to the atmosphere.
Properly covering manure with soil retains the nutrients. Manure injection reduced
ammonia volatilization by over 90% (Jokela and Cote, 1994) when injection was used.
Volatilization was shown to be proportional to pooling of manure on the soil surface
(Chen etal., 2001). Also, odor was reduced with injection (Jokela and Cote, 1994).

Bittrnan et al., (2000) measured ammonia volatilization resulting from broadcast,

AerwayTM and dribble bar band slurry applications. The average ammonia emissions

l3

resulting from dribble bar application was 41% lower than emissions from broadcast
applications. And the average ammonia emissions resulting from AerwayTM applications
were 57% lower than the ammonia emissions compared with broadcast application. The
average ammonia loss for broadcast applied manure was 40% of total applied. Petkau
and May (2001) compared ammonia emissions of sleight foot, dribble bar and AerwayTM
applicators during and after application. Overall, the average ammonia emissions were
not different. However, the AerwayTM had the greatest ammonia emissions during
application but lower after application emissions than the dribble bar once the manure
was on the ground.

1.2.2.2 Crop Response

The negative effects of manure injection on crops are related to the disturbance
caused by the application, poor placement of the nutrients, and the lack of uniform
application. Petkau and May (2001) monitored grass yields plots treated with of sleight
foot, dribble bar and AerwayTM slurry applicators. All applications of manure resulted in
greater yields despite crop disturbance. Even though the sleight foot injector resulted in
the largest losses due to crop damage it also resulted in the largest yields. Dribble bar
yields were similar to the sleight foot yields.

Nutrient placement with respect to the plants is important. Too much manure too
close to the plant can be toxic or inhibit growth (Sawyer et al., 1990). Injection of beef
manure has caused plant stunting, chlorosis, and reduced yield in corn (Sawyer et al.,
1991). However, manure injection more often leads to good quality, high yielding crops
(Mathers and Stewart, 1984). Variability in application explains some the problems.

Sawyer et al (1990) showed that sweep injected manure resulted in a more uniform lateral

14

distribution of manure and inorganic N as compare with knife injected manure. Crops
treated with sweep injection experienced a reduction in the time it took for the above
ground maladies to pass.

Buckley et al. (2001) used axle mounted load cells to apply manure with an
AerwayTM SSD injector. Manure was applied at 0.5x, 1x and 2x recommended ammonia
N rates for 3 cat and 3 barley varieties. Inorganic fertilizers were applied at the same
rates on adjacent plots for comparison. Manure application produced yields similar to
fertilizer application.

1.3 Objectives

The overall objective of this study was to evaluate the field performance of a low
disturbance rolling-tine slurry manure injector. Specific objectives were to:

1. Determine how tillage with a rolling-tine harrow influences initial water

infiltration rates.

2. Assess the uniformity of slurry placement throughout the injection zone.

3. Evaluate changes in soil electrical conductivity following manure slurry

injection, and the stability of the electrical conductivity measurements over
time.

4. Evaluate correlations between electrical conductivity and soil properties.

15

CHAPTER 2

2. METHODS AND MATERIALS

Infiltration rate and application uniformity are of interest for manure injection
implement evaluation. Many manure injection systems are commercially available
including a rolling-tine harrow (Aerwaym) . The tool can be used for tillage in orchards,
pastures, turf grass and cropland. Minimal and aggressive tillage are possible by making
changes in the gang angle. In this study, the AerwayTM was evaluated for its effect on
water infiltration rate, uniformity of application, and effect on soil electrical conductivity.
Images in this thesis are presented in color.

2.1 Rolling-tine harrow

A 3.66 m (12 foot) AerwayTM rolling-tine harrow for low-disturbance slurry
injector was evaluated. The implement weighed 2268 kg (5000 lbs), and 680 kg (1500
lbs) was added for full penetration of the tines. The manure injector was hitched to a
NuhnTM 13627 L (3600 gal), dual axle manure slurry spreader. The spreader’s splash
plate was replaced with a 15 cm (6 inch) hose from the tank to the grinder on the injector
(Appendix C, Figure C5). The power take-off from the tractor was used to drive a
positive displacement pump on the spreader, and a hydraulically actuated butterfly valve
controlled the flow rate to the AerwayTM (Appendix C, Figure C8). The valve allowed
excess flow to the tank for bypass agitation. Power take-off rpm and land speed were
held constant at 2200 rpm and 4.6 kph (2.9 mph) respectively. The application rate was

49100 Lha'l (5,250 gpa) for all treatments receiving manure. The application rate was

16

calculated based on speed, time and mass of manure applied. The manure passed through
a hydraulically powered grinder mounted on top of the AerwayTM (Appendix C, Figure
C4-6). The grinder had two plates that rotated over 18 equicentric, radially configured
outlets connected to the distribution lines (Appendix C, Figure C6). The grinder plates
did not allow slurry to pass through the outlets when they were over the outlets, which
increased the available pressure to the outlets that were not covered and created uniform
flow to each distribution nozzle. The grinder plates also chopped larger solids that might
get caught in 5 cm (2 inch) outlets. The distributor hoses had rubber nozzles on the end
that were positioned close the ground. The hydraulic cylinder used to raise the AerwayTM
for transport was connected to a linkage which pinched the rubber nozzles preventing
flow during transport (Appendix C, Figure C7).

Manure samples were collected from the tank in the field before application. The
manure was agitated in the storage tank and in the field tank to ensure uniform
consistency. Frozen samples were sent to the University of Wisconsin Soil & Forage
Analysis Lab for nutrient analysis (Table 1).

Table 1: Liquid dairy manure analysis

 

 

Progrty Sample 1 Sample 2

g/L lbs/ 1000 gal g/L lbs/1000 gal
Total Nitrogen 3.38 28.21 3.35 27.94
Total P205 1.27 10.57 1.31 10.91
Total K20 3.67 30.67 3.69 30.76
Sulfur 0.36 2.99 0.35 2.96
Moisture 89.70 % 89.70 % 90.10 % 90.10 %
Dry Matter 10.30 % 10.30 % 9.90 % 9.90 %

 

Two sets of experiments were conducted on a Capac sandy loam (fine-loamy,
mixed, active, mesic Aquic Glossudalfs) soil. The first was to evaluate the effects of

rolling-tine harrow tillage without manure. The second was used to evaluate the effects

17

of rolling-tine harrow tillage with manure. Data from the experiments were analyzed
using SASTM (SAS Inc., 2002). Analysis of variance of was done using the PROC
MD{ED procedure in SASTM. Mean separation and pair wise comparisons were made
using the Fischer’s protected Least Significant Difference (LSD) procedure (Kuehl,
2000).
2.2 Tillage with the rolling-tine harrow, no manure

The first experiment was used to evaluate the effects of tillage on initial water
infiltration and residue cover in a Capac soil. The experiment was arranged in a
randomized complete block with four replications. The tillage treatments included: 1) no
tillage, 2) light tillage (0° gang angle), and 3) aggressive tillage (10° gang angle) using
the rolling-tine harrow in untilled wheat stubble. Treatment plots were 3.7 m (12 ft) wide
by 30.5 m (100 ft) long. No manure was applied.
2.2.1 Initial Infiltration Rate

Infiltration rate is a measure of the permeability of the soil. Generally, increasing
tillage increases the infiltration rate since tillage increases pore space and the volume of
adsorption cavities. Increasing the infiltration rate in manure application is important
because it reduces the chance of overland flow and pooling of manure. Pooling can result
in non uniform application, increased volatilization and increased risk of nutrient loss to
runoff.

A double ring infiltrometer was used to measure the water infiltration rate at two
locations within each plot (Appendix C, Figure C10). The double ring infiltrometer
consisted of a 46 cm (18 inch) diameter ring, 46 cm (18 inch) high, a 20 cm (8 inch)

diameter ring, 46 cm (18 inch) high, 2 calibrated water storage columns, and a depth

18

gauge. The columns and rings were plumbed in such a way as to control and measure the
water flowing into each ring. Both rings were driven concentrically 10 cm (4 inches) into
the ground in the plot. Water was first added to the outer ring to a depth of 2.5 cm (1
inch). Water was then added to the inner ring to the same depth at which time the timer
was started (time 1). Equalizing the depth of water in each ring equalized the head. The
water levels in each ring were kept at 2.5 cm (1 in) for an hour. The water level of the
calibrated column connected to the inner ring was recorded every 10 minutes. The water
level of the column connected to the outer ring was not recorded. The infiltration rate for

a given time interval was calculated as:

_ *
Ir = (8' 53),. ISA (Equation 1)
1 ' 2 A

 

where Ir is the infiltration rate, C1 is the column height at time 1, C2 is the column
height at time 2, CA is the column area, T1 is the time 1, T2 is time 2 and RA is the area of
the inner ring (Appendix A, Table A1). Time 1 was the timer start time and time 2 was
10 minutes after. The PROC MIXED model used to analyze infiltration included
treatments as fixed factors, blocks as a random factor, the interaction of blocks with
tillage treatment and the interaction of blocks with north or south sampling positions as
error terms. Least Significant Difference (LSD) pair wise comparisons were made for
significant treatment effects for initial infiltration.
2.2.2 Residue Cover

Residue cover is important for soil moisture retention and erosion reduction.
Residue cover was measured in the middle of the plots used for the infiltration study.
The line transect method was used (Hathaway et al., 1993). A tape measure was laid

diagonally across each plot. The residue presence was observed every 15 cm (6 inch).

19

For example, if there was residue on the soil directly below the 15 cm (6 inch) mark on
the tape then it was recorded as a crop residue intersect. If the soil was bare directly

beneath the mark than it was not counted. The residue cover is given as:

X100 = 9;; * 100 (Equation 2)

where X100 is the percent residue cover, N is the number of crop residue intersects and T,
is the total number of intersects (Appendix A, Table A2). The PROC MD(ED model
used to analyze differences in residue cover included treatments as a fixed factor and
blocks as a random factor. LSD pair wise comparisons were made for significant
treatment effects for residue cover.
2.3 Tillage with the rolling-tine harrow, with manure

The second experiment was used to evaluate the effects of tillage with manure
application on surface manure coverage, soil bulk density, nutrient placement uniformity
and electrical conductivity in a Capac soil. Four tillage treatments were applied with four
replications on wheat stubble in a randomized complete block design. The tillage
treatments were: 1) no tillage and no manure, 2) no tillage with manure, 3) light tillage
(0° gang angle) with manure and 4) aggressive tillage (10° gang angle) with manure.
Treatment plots were 3.6 m (15 ft) wide by 30.5 m (100 ft) long. Manure coverage, bulk
density, soil Bray 1 phosphorous (P) concentration, and soil electrical conductivity (EC)
were measured to evaluate treatment effects.
2.3.1 Surface Manure Coverage

Digital images of the soil surface were taken immediately following application
for assessment of the surface coverage of the manure. The percent manure surface

coverage was estimated as:

20

M SA
TSA

 

PSMC = (Equation 3)

where PSMC is the percent manure surface coverage, MSA is the manure surface area and
TSA is the total surface area. The area of the manure cover was calculated by drawing
polygons over the manure in ArcviewTM and finding the total area of the polygons
(Appendix A, Table A3). The PROC MD(ED model for the analysis of surface manure
coverage included treatments as a fixed factor and blocks as a random factor.
2.3.2 Bulk Density

Tillage affects bulk density by increasing pore space. The bulk density samples
were taken using a slide hammer core sampler (Appendix A, Table A4). The samples
were taken 1 day after application on light and aggressively tilled plots with manure. The
cores were taken on the north and south end of each plot to a depth of 23 cm (9 inch) with
three 7.6 cm (3 inch) incremental samples. The samples were oven dried at 105 °C (221
°F) until constant weight was reached (Blake and Hartge, 1986). The bulk density was
calculated as:

DM
Cv

 

pb= (Equation 4)

where pb is the bulk density, DM is the dry mass and CV is the core volume. The PROC
MIXED model for the analysis of bulk density included treatments as a fixed factor and
blocks as a random factor. Pair wise comparisons were made for significant treatment
effects for bulk density.
2.3.3 Volume and surface area of tilled soil

To aid in identifying slurry placement in the soil profile, fluorescent yellow/ green

dye from Kingscote Chemicals Brightdyes was added to the manure. Liquid dye was

21

chosen over powder for enhanced mixing with the manure. Fluorescent green/yellow dye
was added to liquid manure at 250 ppm. The dye was reported to be visible in water at a
concentration of 1 ppm, and with a black light at 10 ppb. The dye was used to identify
manure placement in the soil. The dye improved the visibility of the manure in contrast
to the soil.

The intent in excavating the injection profile 3 days after manure application was
to reveal the distribution of the manure in soil cavities. Digital images of the soil profile
could then be used to evaluate uniformity. However, the dye manure mixture was not
clearly visible and the black light did not cause the dye to fluoresce.

Rather than recording images of the soil profile and slurry/soil mix insitu., the soil
/ slurry mixture in the soil loosened by the tillage tines was excavated and a powdered
dye was applied to the surface of the tillage cavities. Orthogonal dimension referenced
digital images were taken of the cavities. Estimated dimensions from the pictures were
used to make void models. The 1:1 scale models were made to have the same shape as
the top view of the void. A cloth material was fastened to the cardboard profile as to
hang to the depth indicated in the photos. Coordinate measurements were taken on a 6.5
cm2 (1 in2 ) grid. The coordinates were used to make 3-D views in Arcview (Appendix C,
Figures C18-19). The tilled surface area, void volume (cm3) and surface area of
undisturbed soil in voids were calculated for the light and aggressive void models.

2.3.4 Nutrient Placement Uniformity
Nutrient distribution from manure injection can be assessed by measuring soil

nutrient concentrations around the point of injection (Sawyer et al., 1990). Changes in

22

the nutrient content of the cores reveal where the nutrients have been placed. In this way
nutrient concentration can be used as a tracer of subsurface manure placement.
Phosphorous was used as the tracer to evaluate the uniformity of nutrient
placement throughout the soil profile. The P transect samples were taken at incremental
positions relative to tillage with a 7.6 cm (3 in) diameter Giddings probe. The samples
were divided into depths of 0-7.6 cm (0-3 in), 7.6-15 cm (3-6 in) and 15-23 cm (6-9 in).

The positioning scheme is represented in Figure l.

 

 

 

 

 

 

 

 

Repetition 1 Repetition 2
0 o
0 l, 0 Travel Direction
r X
P1‘P2)‘P3 " Plnpz p3 ' Points ofdeepest
" 0 line penetration
" " x stapling position
0 it 0
19 in 0 o P1= maximum penetration
48 cm 0 0 P2: medium penetration
0 i, 0 P3: least penetration
0 0
5 in o o
15 ch 0 0 0
ti o
it o
0 0 0
l—-—l
7.5 in
19 cm

 

 

 

Figure 1: Position of sampling for phosphorous relative to tillage

The samples were air dried, ground and sent to the Michigan State University Soil and
Plant Nutrient Laboratory where the Bray l — F test (Frank et al., 1998) was used to
measure extractable P (Appendix A, Tables A5-8).

Treatment, position and depth were treated as fixed factors in the PROC MDCED
model for the analysis of nutrient placement. In the analysis, block as a random factor

and the block with treatment interaction, and the block with treatment and position

23

interactions as error terms. Mean separations were conducted using Fishers’s protected
LSD. Soil BC was used as a covariate in a second analysis of the same model. A
covariate is a variable that is related to the response variable of interest (Kuehl, 2000).
Covariates are used to adjust the analysis to reduce experimental error.

2.3.5 Electrical Conductivity

A VerisTM 3100 (Appendix C, Figure C11) was used to measure the soil EC at
depths of 30 cm (1 ft) and 91 cm (3 ft). The tool was used on the entire test site one day
before, 1 day after and 1 week after application of treatments. Two coulters with an
electrical potential between them penetrate the soil. The EC of the soil is measured as
current induced through the volume of soil between the coulters with a voltaic potential.
The VerisTM system uses six coulters. The center pair emit the electrical signal. The two
that are adjacent to the center coulters measure 30 cm (1 ft) EC. The two coulters that
are further apart measure EC to 91 cm (3 ft).

The EC data sets did not have the same number of readings per plot due to speed
variation of the towing vehicle. Using an unequal number of values in AN OVA may bias
results to plots with the highest or lowest number of readings. For this reason the values
were used to make an interpolated grid so that an equal number of readings could be
extracted from each plot. A grid size of l.5x1.5 m (5x5 feet) was used to ensure that at
least one actual EC value was used per grid point. Inverse distance weighting, with
power of 2, was used to interpolate the EC data. An equal number of interpolated values
was extracted from the interpolated grids (Appendix A, Figures A1-6) and used in the
ANOVA analysis. Only the points located in the center of the plots close to the location

of the original data points were extracted. Extracted interpolated grid values (EIGV)

24

from the plot edges were undesirable because they did not reflect the values for the plot
but an interpolation of the values from both plots. Absolute EIGV for one day before,
one day after and one week after application (Appendix A, Table A9-l4) were used in
ANOVA to find differences between treatments.

Soil EC is dependent on soil properties so both were measured using a
management zone approach. The initial 0.3 m (1 ft) measurements were mapped. Three
management zones were established based on the 0.3 m (1 ft) EC interpolated values. A
total of 17 flags were placed in 3 zones with more flags in larger zones. The flags were
geo-referenced using a Trimble® AgGPS 124 reciever. The nearest neighbor method
was used in Arcview GIS to extract soil EC values for each flag.

Soil cores were taken at the flags before treatments to a depth of 0.91 m (3 ft).
The core was divided into depths of 0-0.15 m (0-O.5 ft), 0.15-0.30 m (0.5-1 it), 0.30-0.61
m (1-2 it) and 0.61-0.91m (2-3 ft). The samples were sent to A&L Great Lakes
Laboratories for analysis. The measured soil properties were organic matter (OM;
Combs and Nathan, 1998), phosphorous (P; Frank et al., 1998), potassium (K; Wamke
and Brown, 1998), magnesium (Mg; Wamke and Brown, 1998), calcium (Ca; Wamke
and Brown, 1998), pH (Watson and Brown, 1998), and cation exchange capacity (CEC;
Wamke and Brown, 1998; Appendix A, Tables AIS-18).

Sub-samples of the flag cores were taken to measure gravimetric soil moisture
(Appendix A, Table 20). Samples were stored at 4° C (40° F) in air tight bags. The

samples were weighed to the nearest 0.01 g before drying. The samples were air dried

for a few days before being oven dried at 105° C (221° F) to constant weight (Gardener,

25

1986). After drying, samples were reweighed. The gravimetric soil moisture content was

calculated as:

_(WM -DM)
M______

P
3 DM

(Equation 5)

where PSM is the percent soil moisture, WM is the wet mass of the soil, and DM is the dry
mass of the soil.

The soil EC PROC MIXED model used tillage treatments as a fixed factor, block
as a random factor and the block treatment interaction as an error term. Multiple EC
measurements for each plot were treated as sub samples. Pair wise LSD comparisons
were made for mean separation of significant treatment effects.

Multiple regression was performed with the PROC REG stepwise procedure in
SAS TM. Soil BC was used as the dependent variable and organic matter, phosphorous,
potassium, magnesium, calcium, pH, cation exchange capacity, gravimetric soil moisture,

and bulk density were used as the independent variables.

26

CHAPTER 3

3. RESULTS AND DISCUSSION

Two sets of experiments were conducted. The first was to evaluate the effects of
rolling-tine harrow tillage without manure. The second was used to evaluate the effects
of rolling-tine harrow tillage with manure. Data for both sets of experiments are tabled in
Appendix A. The AN OVA tables are given in Appendix B.
3.1 Tillage with the rolling-tine harrow, no manure
3.1.1 Initial Infiltration Rate

An objective of the infiltration rate study was to determine how tillage provided
by the rolling tine harrow influenced the initial infiltration rate. The initial infiltration
rate is important because it affects how quickly the slurry may be incorporated in the soil
profile. Rapid infiltration may reduce overland flow, pooling, and minimize odor and
volatile N loss. Infiltration rates over longer time intervals were not of interest. The
tillage treatments had significantly different (P<0.05) infiltration rates during the first ten
minutes of infiltration (Appendix B, Table Bl). The LSD procedure was used to evaluate
differences between the means of the ten minute infiltration rates for each tillage
treatment (Table 2).

Table 2: Ten minute water infiltration rates for a loam soil with a rolling-tine harrow

 

 

 

Effect Ten Minute Infiltration Rate
cm/hr in/hr

No tillage 16.1 a 6.34 a

Light tillage 13.5 a 5.31 a

Aggressive tillage 22.4 b 8.82 b

LSD(0.05) 2.9 1.14

 

Means within each column followed by the same letter are not significantly different (p50.05).

27

The ten minute infiltration rate mean for light tillage was not different from no tillage.
Light tillage was expected to increase the contact area and loosen the soil to some degree.
The ten minute infiltration rates of the aggressively tilled plots were greatest and were
different from plots receiving light or no tillage. The difference was likely due to the
fracturing effect the aggressive tillage had on the soil. Presumably, more aggressive
tillage may also speed the infiltration of manure slurry, reduce overland flow and
pooling, increase soil/slurry interface, and improve the uniformity of nutrient placement.
3.1.2 Residue Cover

Residue cover is important because it can reduce erosion by absorbing rain drop kinetic
energy and inhibit overland flow. Tillage resulted in significantly different (P5010)
residue coverage (Appendix B, Table B2). There was no difference between the residue
cover of no tillage and light tillage. Aggressive tillage buried a greater amount of residue
compared with light tillage or no tillage (Table 3).

Table 3: Wheat straw residue cover following tillage with a rolling-tine harrow on a loam
soil.

 

 

Effect Residue Cover (%)
No tillage 55.5 a

Light tillage 55.7 a

Aggressive tillage 41.9 b

LSD(0.10) 8.6

 

Means within each column followed by the same letter are not significantly different (pSO. 10).

3.2 Tillage with the rolling-tine harrow, with manure
3.2.1 Surface Manure Coverage

Surface manure coverage of the tilled plots was measured to evaluate the effect of
low disturbance tillage on slurry placement (Appendix A, Table A3). The percent cover
of the manure application without tillage was not calculated because tire traffic from the

slurry injector interfered with the surface application (Appendix C, Figure C20). With

28

tillage the tines were in the soil, and the tires were off the ground such that no
interference occurred. No difference (P3010) between manure surface coverage for light
and aggressive tillage were found. This indicates plot scale uniform application for both
treatments (Appendix B, Table B3). Taking the surface manure cover images
immediately after treatment application did not allow time for the manure to infiltrate
into the soil irrespective of tillage.
3.2.2 Bulk Density

Soil BD was measured on both ends of the light and aggressively tilled plots
(Appendix A, Table A4). Tillage, depth and their interaction had significant effects
(PSO.12) on soil BD (Appendix B, Table B4). Bulk densities for light and aggressive
tillage were not significantly different (P3012) for 7.6-15 cm (3-6 in) depth (Table B4).
Bulk densities at depths 0-7.6 cm (0-3 in) and 12-23 cm (6-9 in) were the same for light
and aggressive tillage however soil bulk density at 7 .6-15 cm (3-6 in) was significantly
smaller in aggressive tillage. For light tillage soil bulk density at 0-7.6 cm (0-3 in) was
smaller than that of the deeper soil. Aggressive tillage increased soil disturbance at a
greater depth with bulk density at both 0-7.6 cm (0-3 in) and 7 .6-1 5 cm (3-6 in) being
significantly smaller than the density at the deeper depth.

Table 4: Soil bulk density (g/cm3) following light and aggressive tillage

 

 

 

Treatment
Depth Ight tillage Aggressive tillage
0-7-6 cm (0‘3 in) 1.23 xa 1.21 xa
7.6-15 cm (3-6 in) 1.47 xb 1.28 ya
12-23 cm (6-9 in) 1.48 xb 1.42 xb

 

Means within each row followed by the same letter (x-y) are not significantly different (LSD0_12=0.09)
Means within each column followed by the same letter (a-b) are not significantly different (LSD0,.2)=0.06

29

3.2.3 Volume and surface area of tilled soil

The fluorescent green/yellow dye was not an effective tracer for this application.
The dye only fluoresced in solution. This greatly hindered empirical excavation.
Orthogonal images of tine cavities were made by carefully removing the manure and
back fill and highlighting the cavity with fluorescent powder (Appendix C, Figures C12-

15). The images were used to make 3-D models in Arcview (Appendix C, Figures C18-

 

 

 

19).
Table 5: Volume and surface area of tilled soil.
Light tillage Aggressive tillage
SI English SI English
Tilled surface area 46 cm2 7.1 in2 280 cm2 43 m2
Tilled soil volume 120 cm3 7.3 in3 1000 cm3 61
Void side wall surface area 240 cm2 37 in2 500 cm2 76 in2

 

l L = 1000 cm3
lgallon = 3.78 L

The tilled surface area, volume and void sidewall surface area of the 3-D voids
created by light tillage were estimated as 46 cm2 (7.1 inz), 120 cm3 (7.3 in3; 0.12 L, 0.03
gallons) and 240 cm2 (37 in2 ), respectively. The tilled surface area, volume and void
sidewall surface area of the 3-D voids created by aggressive tillage were estimated as
280 cm2 (43 inz), 1000 cm3 (61 in3; 1.0 L, 0.27gallons) and 500 cm2 (77 in2 ),
respectively. The tilled surface area was the planar area looking down at the void while
standing above it. The void volume was the volume of manure the void could hold
(neglecting backfill). The void sidewall surface area was the total inside surface area of
the void or the area where untilled soil and slurry would meet if the void was filled with
manure. The void volume and void volume and void sidewall surface area were larger
for the aggressive tillage indicating that more manure may be applied with aggressive

tillage.

30

3.2.4 Nutrient Placement Uniformity

Manure application uniformity was evaluated using soil phosphorous (P)
concentration measured at three positions and three depths relative to tillage (Appendix
A, Tables A5-8). Bray l-P was used as a tracer for slurry placement. Soil P
concentration measured with respect to tillage was affected (P=0.05) by depth, position,
the interaction of treatment with position and depth, the interaction of depth with
treatment, the interaction of depth with position (Appendix B, Table B5). Comparisons
between depths and positions relative to tine penetration were made for each treatment
(Tables 6).

Table 6: Bray l-P at 3 depths and 3 positions relative to tine penetration for 4 individual
tillage and manure treatments

 

 

 

 

Depth Bray I—P measured at LSD1josmons (0.10)
Tine Penetration“
Maximum Medium Least
PPm
No tillage / no manure
0-7.6 cm (0-3 in) 38 xa 35 xa 36 xa 17
7.6-15 cm(3-6 in) 21 xb 29 xa 25 xa 11
15-23 cm (6-9 in) 23 xb l9 xyb 12 yb 8.8
No tillage w/ manure
0-7.6 cm (0-3 in) 54 xa 53 xa 51 xa l7
7.6-15 cm(3-6 in) 25 xb 25 xb 27 xb 11
15-23 cm (6-9 in) 13 xc l3 xc 19 xc 8.8
Light tillage w/ manure
0-7.6 cm (0-3 in) 73 xa 61 xya 51 ya 17
7.6-15 cm(3-6 in) 43 xb 29 yb 30 yb 11
15-23 cm (6-9 in) 24 xc 13 yo l7 xc 8.8
Aggressive tillage w/ manure
0-7.6 cm (0-3 in) 91 xa 8O xa 59 ya 17
7.6-15 cm(3-6 in) 32 xb 29 xb 27 xb 11
15-23 cm (6-9 in) 15 xc 13 xc 13 xc 8.8

 

* In treatments without tillage soil samples were taken at the same relative positions and spacing as in
treatments with tillage

Means within each column for a treatment followed by the same letter (a-c) are not significantly different

(p=0.05).

Means within each row followed by the same letter (x-y) are not significantly different (p=0.05).

LSDD‘p'h L20.10)= 8.6, Lsompm"3(0.10) = 12, LSDW'3(O.1O)=6.6

31

Soil P concentrations decreased with depth regardless of tillage or tine
penetration. Soil P concentrations showed no difference between tine position without
tillage. The greatest soil P concentrations were recorded at positions of greatest
penetration where soil was disturbed.

The same trend of soil P decreasing with depth was observed when data from‘all
treatments were combined (Table 7). Comparing the soil P concentration at the 0-7.6 cm
(0-3 in) layer, soil P concentration at position 1 (maximum penetration) was not different
from position 2 (medium penetration). Position 2 was not different from position 3 at O-
7.6 cm (0-3 in). However the means of position 1 and 3 were different (Table 7). Manure
filled the tillage depressions and caused greater P concentration in the depressions and
slightly lower P concentration where there was less penetration. There was no difference
between the positions at depths greater than 7.6 cm (3 in).

Table 7: Bray l-P means for the interaction of depth and position for all treatments

 

 

 

 

Depth Tine Penetration Position LSDPOSi’imm. 05)
Maximum Medium Least
PPm
0-7.6 cm (0-3 in) 64 ax 57 axy 49 ay 10
7.6-15 cm(3-6 in) 30 bx 28 bx 27 bx 6.6
15-23 cm 6-9 in) 19 ex 14 ex 16 ex 5.2
LSDDepth " 0.05) 5.2 5.2 5.2
LSDD‘p‘h”3(O.05) 7.4 7.4 7.4
LSDDWW'3(0.05) 4.0 4.0 4.0

 

Means within each column followed by the same letter (a-c) are not significantly different. (p=0.05).
Means within each row followed by the same letter (x-y) are not significantly different (p=0.05).

Effect of tillage on soil P concentration was different at different depths (p=0.05,
Table B5). Comparisons between tillage treatments were made at each depth to
understand the interaction of tillage with depth. There was a difference in the magnitude
of the soil P concentration at 0-7.6 cm (0-3 in; Table 8) The aggressive tillage with

manure had greater P concentrations than all of the other treatments at 0-7.6 cm (0-3 in;

32

Table 8). Greater concentrations in tilled areas indicate less overland flow and greater
infiltration of manure nutrients into the soil profile. The lowest P levels were recorded
where there was no tillage and no manure applied. There was no difference between soil

P in the 0-3 inch layer between the surface treatment and light tillage (Table 8).

Table 8: Bray l-P means for the interaction of depth and treatment

 

 

 

 

Depth L S DTreatments
Treatment (0.05)
No tillage / No Light Aggressive
no tillage / tillage / Tillage /
manure P manure P manure P Manure P
PPm

0-7.6 cm (0-3 in) 36 ax 53 ay 61 ay 77 az 15
7.6-15 cm(3-6 in) 25 bx 26 bx 34 bx 29 bx 12
15-23 cm (6-9 in) 18 ex 15 ex 18 ex 15 ex 11
LSDWh "2‘0”” 6.0 6.0 6.0
LSDDCpthl’Smps) 8.5 8.5 8.5
LSDWW-i‘w, 4.6 4.6 4.6

 

Means within each column followed by the same letter (a-c) are not significantly different. (p=0.05).
Means within each row followed by the same letter (x-y) are not significantly different (p=0.05).

3.2.5 Analysis of soil P with soil EC as covariate

Natural variability in soil P concentrations between plots existed before the
experiment. Using the difference between soil P values before and after application of
treatments is one way of reducing this experimental error. Using a covariate is another
way.

A covariate is a variable that has a relationship with the response variable and
varies among the experimental units. In the analysis of experimental data a covariate can
be used to help explain experimental variability. A covariate can increase the accuracy of
the results of the analysis by reducing experimental error. Soil EC was used as the
covariate in the analysis of nutrient placement uniformity. The ANCOVA results were

compared with the ANOVA results separately for each depth. The treatment effect was

33

significant (p=0.05) only at depth O-7.6 cm (0-3 in), so only that depth was used for
analyses comparison (Tables B6 and B7). However, EC had a significant (p<0.05) effect
on soil P concentrations regardless of depth (Appendix B, Table B6). The significant
effects were treatment and position. The AN COVA resulted in lower standard errors and
therefore was more accurate than ANOVA. The ANCOVA had a lower Akaike's
Information Criterion (AIC) at the 0-7.6 cm (0-3 in) depth indicating a better model
(Table B6 and B7).

Comparisons between positions relative to tine penetration were made with and
without soil EC as a covariate (Table 9). Using the soil EC as a covariate increased the
accuracy as indicated by the lower standard error of treatment mean (Table 9). Soil P
concentration was higher at positions of maximum and medium tine penetration and
lower at minimum tine penetration with the soil EC as a covariate (Table 9). The
medium penetration soil P concentrations were not different fi'om the soil P
concentrations at the maximum or minimum when compared without using soil EC as
covariate (Table 9). Using the covariate makes the distinction clear between the
positions. Soil P concentration was not different at positions of medium and minimum
penetration with ANOVA. Using ANCOVA soil P concentration was significantly
smaller at minimum penetration than at medium penetration (Table 9).

Comparisons among P concentrations between tillage treatments were made with
soil EC as a covariate (Table 11) for the 0-7.6 cm (0-3 in) depth. Linear regression
slopes between soil P concentrations and EC values were significantly different for the

treatments (Table 10). Figure 2 shows the graph of the regressions for each treatment.

34

Table 9: Mean Bray l-P concentrations at different tine penetration positions at 0-7.6 cm
(0-3 in) obtained from the data analyses with and without soil EC.

 

 

 

 

Analysis with Standard Tine Penetration Position
or without the error of Maximum Medium Minimum
covariate treatment
mean
131”“

ANOVA 1 1.0 63.4a* 57.1ab 49.1b

0.187‘1' 0.0051 0.101§
ANCOVA 6.6 65.6a 59.2a 51.2b
with EC 0.1731: 0.0041 0.091 g

 

* means within the same row followed by the same letter are not significantly different (p<0. 1)
T level of significance for comparing Maximum and Medium penetration positions

I level of significance for comparing Maximum and Minimum penetration positions

9‘ level of significance for comparing Medium and Minimum penetration positions

Table 10: Relationships between soil P concentrations and soil EC at different

manure-tillage treatments at 0-7.6 cm (0-3 in).

 

 

 

Treatment Linear regression equation

Intercept Slope 1'2
No tillage / no manure 83.9 -3.2ab * 0.63 ‘1‘
No tillage / manure 80.4 -1.95 a 0.54
Light tillage / manure 175.6 -6.2c 0.72

Aggressive tillage / manure 143.9

-4.65 bc 0.29

 

* Regression slopes with the same letters are not significantly different from each other (p<0.05).

1' Regression is significant (p<0.01).

Soil P (ppm) versus 1 it pro-application soil EC (mS/m)

 

 

 

 

 

  

 

 

|
l 16° , moor
l 14o-—-— _ ,_ -..t ___.___.,_ I.
+ .Suriace I
1201“ ‘ . + _l,_,j Nhnure I l
+ Light : '
’ 100 ii ”A - - Tillage
l? 0 z i o Aggressive y
'g 8° ““ T ’ 7’ Tillage l .
. o. . _
. 60 l a
, o a m -
2. .- 0 e
O ' ' I I
0 5 10 15 20 25 30

1 it pro-application sci E: (rrS/m)

Figure 2: Soil P (ppm) verses 1 ft pre-application soil EC (mS/m)

35

Because the slopes of soil P concentration versus soil EC from different
treatments were significantly different, the mean separation for AN COVA was conducted
at three different soil EC levels. The values used corresponded to the 25th, 50th and 75th
percentile soil EC groups or EC values of 8.9, 15.6 and 20.5 (mS/m) respectively (Table
11).

Table 11. Mean soil P concentrations at different treatments at 0-7.6 cm (0-3 in) obtained

from the data analyses with and without EC as a covariate. Standard errors for treatment
means are shown in parenthesis.

 

 

 

 

Treatment
No tillage — No tillage + Light tillage + Aggressive
no manure manure manure tillage + manure
ppm

ANOVA
36 (12.3) a* 52 (12.3) ab 61 (12.3)b 76 (12.3)c
0-139T 0-0331 0.003§ 0.393 ll 0.038# 0.160"

ANCOVA

Mean separations at

EC=8.9 56.0 (12.2) a* 63.6 (7.7) a 121.3 (12.3) b 103.4 (10.0) b
0.364 1 0.0021 0.003§ 0,003 || 0,005# 0.144"

EC=15.6 34.0 (6.9) a* 50.1 (6.9) a 79.3 (7.5) b 71.6 (7.0) b
0.0291 0.0011. 0.001§ 0.006 H 0.010# 0.293"

EC=20.5 17.9 (8.9) a* 40.3 (7.8) b 48.5 (7.2) b 48.3( 10.3) b
0.02811 0.0081 0.017§ 0.24] H 0.388# 0.984"

"' means within the same row followed by the same letter are not significantly different (p<0.05)

1' level of significance for comparing No tillage and No tillage_Manure treatments

I level of significance for comparing No tillage and Light tillage_Manure treatments

§ level of significance for comparing No tillage and Aggressive tillage_Manure

H level of significance for comparing No tillage_Manure and Light tillage_Manure treatments
# level of significance for comparing No tillage_Manure and Aggressive tillage_Manure treatments
*

* level of significance for comparing Light tillage_Manure and Aggressive tillage_Manure treatments

The comparisons of soil P concentrations between treatments with and without
the covariate also resulted in different conclusions. Using the covariate did not indicate
that aggressive tillage resulted in the greatest soil P concentrations at O-7.6 cm (0-3 in) as
was demonstrated without the covariate (Tables 11). Using the covariate lead to

conclusions that light and aggressive tillage treatments had higher soil P concentrations

36

than the control and surface applied plots for 25th and 50th percentile soil EC values.
However, for the 75th percentile EC value, the soil P concentrations for the control were
lower than all other treatments which were not different from each other.
3.2.6 Electrical Conductivity

Soil EC values were measured for each tillage treatment (Appendix A, Tables A9-
A14). Soil EC values at the 91 cm (3 ft) depth were not significantly different (P30.l)
between tillage treatments (Appendix B, Tables B8-10). Soil EC values at the 30 cm (1
ft) depth were different (P30.1) for tillage treatments (Appendix B, Tables B12-l3). The
combinations of tillage and manure used as treatments caused soil EC values to change
differently. Plots treated with manure with no or light tillage had higher soil EC than the
control and the aggressively tilled plots (Table 12). It could be that the manure
application increased soil EC because treatments with manure and no or light tillage had
higher soil EC. Aggressive tillage may decrease soil BC by decreasing soil continuity
and thus conductivity.

Table12: Soil EC (mS/m) 30 cm (1 ft) following tillage treatments

 

 

1 day after 1 week after
Effect application application

EC (mS/m) EC (mS/m)
No tillage / no manure 12.0 a 15.3 a
No tillage / manure 16.5 be 18.9 bc
Light tillage / manure 16.9 b 20.8 b
Aggressive tillage / manure 13.0 ac 17.2 ac
LSD(0.10) 3 .6 3 .4

 

Means within each column followed by the same letter (a-c) are not significantly different (p30.10).

Grouping soils by soil EC measurement is a way to distinguish soils sharing
similar characteristics. The geo-referenced soil EC values were mapped and the plot area

was divided into 3 soil EC zones. Flags were placed in the zones and were used to mark

37

locations for soil sampling within the zones. Figure 3 shows the zone divisions and the

flag locations. The EC values ranged from 4.2 to 26.4 mS/m.

 

 

I ' I

9

|'P2

4.2 to 9.8 ”,3
I'P2
I I .a ' '
BLOCK 1 BLOCK 2 BLOCK 3 BLOCK 4
f-Flag I -BlockCorner

 

 

 

Figure 3: Prc-application 1 foot interpolated EC

Soil properties were measured at the flags (Appendix A, Tables A15-A21). Soil
properties of samples at the flags were treated as independent variables. Pairwise
correlations were made between the independent variables to a depth of
30 cm (12 in, Table 13)).

Stepwise regression was used to find significant (p<0.10) relationships between
the pre-application nearest neighbor soil EC values at the flags and the pro-application
soil properties measured at the flags (Table 14). Soil Mg was the most common
reoccurring significant independent variable in the relationships. Magnesium and percent
organic matter were positively correlated with soil EC. Percent sand was negatively
correlated with soil EC. In contrast Johnson et al., (2001) found organic matter to be
negatively correlated with soil EC. Johnson et al., (2001) also found percent clay to be
positively correlated with soil EC. This agrees with our results of having percent sand

negatively correlated with soil EC as percent sand increased percent clay decreased.

38

Table 13: Independent 0-30 cm (0-12 in) soil parameter Pearson correlation coefficients
and p value matrix

 

 

EC elevation OM P K Mg Ca pH CEC sand silt clay BD SM
EC 1.00
1.
Elevation‘ -0.7 1.00
1 0.00 0.00
OM ‘ 0.66 -0.77 1.00
1 0.00 0.00
Plppm ‘ -0.63 0.36 -0.25 1.00
1 0.01 0.16 0.34
Kppm ‘ -0.39 0.29 -0.28 0.81 1.00
1 0.12 0.25 0.28 <.0001
Mgppm“ 0.91 -0.74 0.62 -0.76 -0.47 1.00
1 <.0001 0.00 0.01 0.00 0.06
Cappm‘ 0.86 -0.86 0.84 -0.62 -0.50 0.92 1.00
1 <.0001 <.0001 <.0001 0.01 0.04 <.0001
pH‘ 0.71 -0.36 0.19 -0.82 0510.84 0.64 1.00
1 0.00 0.16 0.46 <.0001 0.04 <.0001 0.01
CEC‘ 0.78 -0.93 0.88 -0.42 -0.36 0.81 0.95 0.42 1.00
1 0.00 <.0001 <.0001 0.09 0.15 <.0001 <.0001 0.09
sand’ -0.75 0.49 -0.73 0.46 0.37 -0.65 -0.73 -0.42 -0.63 1.00
1 0.00 0.04 0.00 0.07 0.14 0.00 0.00 0.09 0.01
silt‘ 0.14 0.26 0.16 -0.09 -0.06 0.09 0.13 0.23 -0.08 -0.491.00
1 0.59 0.32 0.53 0.74 0.81 0.73 0.63 0.37 0.76 0.05
Clay"l 0.82 -0.85 0.80 -0.59 -0.54 0.82 0.88 0.47 0.89 -0.75 -0.11 1.00
1 <.0001 <.0001 0.00 0.01 0.03 <.0001 <.0001 0.06 <.0001 0.00 0.66
BD‘ -0.30 0.31 -0.55 0.25 0.43 -0.22 -0.39 0.03 -0.37 0.52 -0.18 -0.46 1.00
1' 0.25 0.23 0.02 0.34 0.08 0.41 0.12 0.92 0.14 0.03 0.48 0.06
SM ‘1 0.68 -0.40 0.25 -0.64 -0.35 0.73 0.61 0.68 0.50 -0.47 0.21 0.48 0081.00
1 0.00 0.11 0.32 0.01 0.17 0.00 0.01 0.00 0.04 0.06 0.42 0.05 0.77

 

* Pearson correlation coeffecient
1 level of significance of Pearson correlation coefficient
:1 Sample from 0-6 in

Table 14: ANOVA of stepwise regression parameter estimates of soil EC

 

 

 

 

 

 

 

Variable DF Parameter Estimate T value Pr>t

30 cm (1 ft) BC with 0-15 cm (005 ft) soil properties at flag measurements
Intercept l -4.24 -2. 15 0.049

OM % l 1.71 2.43 0.029

Mg ppm 1 0.0378 5.75 <.0001

30 cm (1 it) EC with 15-30 cm (0.5-1 ft) soil properties at flag measurements
Intercept 1 7.71 2.41 0.03

Mg ppm 1 0.032 5.90 <.0001

Sand % 1 -0.079 -1.83 0.088

30 cm (1 ft) BC with 0-30cm (0-1ft)* soil properties at flag measurements
Intercept 1 10.81 2.28 0.039

Mg ppm 1 0.035 6.02 <.0001

Sand % l -0.16 -2.23 0.0425

 

* Average of 0-15 cm (0-0.5 ft) and 15-30 cm (0.5-1 ft) measured soil property values

39

Chapter 4

4. CONCLUSIONS

Small scale uniformity of application can be altered using tillage treatments. The

uniformity of broadcast application is diminished as slurry flows overland and pools.

Tillage can be used to increase the soil slurry interface and infiltration of slurry nutrients

into the soil. On a field scale, this is helps to keep the application uniform. However, on

a smaller scale the nutrient distribution is variable with peak concentrations where tine

penetration was the greatest.

1.

Aggressive tillage provided by the rolling-tine harrow increased the initial
infiltration rate of a sandy loam soil compared to light tillage.

Aggressive tillage decreased residue cover compared to less aggressive tillage.
Residue cover for light tillage and no tillage were not different.

The greatest P concentrations were found where the tines had the most penetration
at the 0-7.6 cm (0-3 in) depth. P concentration decreased with less penetration.
Increasing tillage intensity created depressions to hold manure on the soil surface.
The depressions filled with manure and resulted in greater soil P levels in the O-
7.6 cm (0-3 in) layer.

Using soil EC as a covariate increased the accuracy of the analysis of soil P by
decreasing the standard error of the treatment mean.

The 91 cm (3 ft) 8011 EC values were not different for tillage treatments.

40

6. The 30 cm (1 ft) soil EC values were different for tillage treatments. Light tillage
with manure and no tillage with manure increased soil EC. Soil EC values for
aggressively tilled plots were not different than plots receiving no tillage and no

manure.

41

1.

CHAPTER 5
5. RECOMIVIENDATIONS

The infiltration study could be improved in a few ways. Samples should be taken
in close groups. This might alleviate effects caused by soil variability. Because
the initial infiltration rate is of interest, shortening the time of measured
infiltration may be helpful.

The problem of tracing manure in the soil after injection is still an issue. Using
phosphorous as a tracer worked to a degree. The fundamental problem of using
phosphorous is that it is already present and it does not move through the soil as
some other nutrients do. However, the variability of background phosphorous in
the application uniformity study may have contributed to insignificant differences
in means at depths greater than 3 inches.

Potassium bromide (KBr) is a popular tracer used in many soil and water studies.
It is naturally occurring only at very low concentration. It is highly soluble and
moves with moisture. The challenge is to apply at a rate that is measurable yet
has negligible crop response. A pilot scale manure application study with
multiple KBr concentrations should be applied and measured using standard
methods and procedures.

A rainfall simulation study was started to evaluate the effect of the tillage
treatments on runoff volume and nutrient concentrations. A portable rainfall

simulator was used but was damaged by weather. Although some samples were

42

collected there were no replications therefore the study was not presented in this
thesis. There is much to gained by continuing the runoff study. The rainfall
simulator needs runoff collection improvements to ensure collection of all runoff,
and deter collection of non-runoff water. Other improvements could include
wheels on one side of the simulator for ergonomic, one person, plot to plot
transport, and retractable shielding tarps. Runoff should be collected in a way

that allows tracking of runoff rates.

43

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control-sediment. USDA and EPA. Washington DC.

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Shanahan. 2001. F ield-scale electrical conductivity mapping for delineating soil
condition. Soil Science Society American Journal 65: 1829-1837.

J okela, W., and D. Cote. 1994. Options for direct incorporation of liquid manure.
proceedings from the liquid application systems conference. Northeast Regional
Agricultural Engineering Service. Rochester, NY. pp.

Koolen A.J., and H. Kuipers. 1983. Agricultural Soil Mechanics. Springer-Verlag.
N.Y.

Kravchenko, A.N., Bollero, G.A., Omonode, R.A., and D.G. Bullock. 2002.
Quantitative mapping of soil drainage classes using topographical data and soil
electrical conductivity. Soil Science Society of America. v. 66 p. 235-243.

Kuehl, R.O.. 2000. Design of Experiments: Statistical Principles of Research Design
and Analysis 2"d edition. Duxbury Press. NY.

45

Lague, C.. 1991. Design of a semi-liquid dairy cattle manure spreader/injector.
Applied Engineering in Agriculture Vol. 7(6): 655-660.

Mathers, A. C., and B. A. Stewart. 1984. Manure effects on crop yields and soil
properties. TRANS of the ASAE 27(4): 1022-1026.

McLaughlin, N., G. J. Wall, B. A. Grant, and D. J. King. 1998. The effects of livestock
manure application methods on water quality, focusing on nitrogen and bacteria
transport in soil. COESA Report No.: RES/MAN-005/97. Ontario, Canada.

Morgan, M., D. Ess, S. L. Rawlins, and J. C. Siemens 1997. The Precision-Farming
Guide for Agriculturists. Deere & Company. Moline, IL.

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ASAE 22(5): 963-966

Sawyer, J. E., M. A. Schmitt, and R. G. Hoeft. 1990. Inorganic nitrogen distribution and
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46

Thompson, A. L., F. Ghidey, and T. P. Regrni. 2001. Raindrop energy effects on
chemical sediment transport. TRANS of the ASAE 44(4): 835-841.

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Brown (ed.). Recommended chemical soil test procedures for the north central
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Agricultural Experiment Station

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(ed.). Recommended chemical soil test procedures for the north central region.
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47

APPENDIX A

Table A1: Ten Minute soil infiltration rates

 

 

 

 

 

10 min infiltration (cm/hr)
Block no tillage light tillage aggressive tillage
North South North South North South
cm/hr
l 8.8 20.8 12.8 21.0 11.3
2 17.55 16.95 7.65 13.2 29.3
3 11.7 18.45 12.45 10.05 25.2
4 17.6 16.8 16.8 14.3 21.8
1 in = 2.54 cm
Table A2: Percent residue cover
Block No tillage Light tillage Aggressive Tillage

 

1 51.7 50.0
2 58.3 61.7
3 45.0 48.3
4 66.7 58.3

 

Table A3: Surface manure coverage

 

 

Block Treatment Manure Cover (%)
1 aggressive tillage 40.5
2 aggressive tillage 44.2
3 aggressive tillage 43.1
4 aggressive tillage 47.2
1 light tillage 41.0
2 light tillage 43.2
3 light tillage 30.0
4 light tillage 35.2

 

48

Table A4: Soil bulk density north and south ends of plots after slurry application

(21 August 2002)

 

 

 

Sample
Block location Treatment 0-7.6 cm depth 7.6-15 cm depth 15-23 cm depth
g/cm3
1 North light tillage 1.30 1.54 1.64
1 Smith light tillage 1.20 1.45 1.58
2 North light tillage 1.09 1.46 1.41
2 South light tillage 1.39 1.50 1.47
3 North light tillage 1.23 1.43 1.43
3 South light tillage 1.05 1.34 1.36
4 North light tillage 1.40 1.57 1.53
4 South light tillage 1.21 1.43 1.43
1 North aggressive tillage 1.29 1.3 8 1.51
1 South aggressive tillage 1.29 1.24 1.46
2 North aggressive tillage 1.13 1.40 1.33
2 South aggressive tillage 1.19 1.24 1.28
3 North aggressive tillage 1.22 1.41 1.53
3 South aggressive tillage 1.25 1.18 1.37
4 North aggressive tillage 1.24 1.36 1.48
4 South aggressive tfige 1.05 1 .02 1 .43

 

Table A5: Soil P levels at 3 depths and 3 positions relative to tillage for no tillage

and no manure

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No tillage and no manure soil P concentrations
Block 1 Block 2 Block 3 Block 4
Repetition l 2 1 2 l 2 1 2
Position 1[2[3 1[2[31121311213 11213 112L3 11213 11213
ppm
0-7.6cm 62 64 60 60 56 56 31 25 28 30 27 26 12 16 15 18 16 15 47 50 47 42 27 42
7.6-15cm 16 39 32 38 60 55 18 20 14 18 24 20 8 8 lo 13 11 14 31 47 31 29 24 27
15-23cm 42 2016 32 45161517 9141214 6 9 5 8 6 7 20 2510 4316 20
l lbs/acre = 2*ppm
lin=2.54cm
Table A6: Soil P levels at 3 depths and 3 positions relative to tillage for no tillage
withmanure
No tillage with manure soil P concentrations
Block 1 Block 2 Block 3 Block 4
Repetition 1 2 l 2 l 2 l 2
Position 112131121311213112131[2[311213ll21311213
ppm
0-7.6cm 75 78 73 56 73 75 58 49 53 62 51 42 39 40 45 55 46 48 50 52 37 33 36 34
7.6-15cm 38 42 30 42 37 64 25 25 21 26 28 21 18 ll 15 29 16 23 16 20 18 9 17 22
15-23cm l3 14 18 14 15 58 12 20 12 13 15 12 l7 l4 12 20 10 20 6 9.5 7 6 6 13

 

l lbs/acre = 2*ppm
1 in = 2.54 cm

49

 

Table A7: Soil P levels at 3 depths and 3 positions relative to tillage for light

tillage with manure

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Light tillage with manure soil P concentrations
Block 1 Block 2 Block 3 Block 4
Repetition l 2 l 2 l 2 l 2
Position 1[2[3 1[2131121311213 llfl3112131121311213
ppm
0-7.6cm 150 124 113 136 97 66 45 56 17 51 49 29 62 32 39 46 55 51 36 37 50 54 34 43
7.6-15cm 97 70 80 97 48 40 13 15 9 37 15 25 36 17 19 23 29 34 18 19 ll 25 21 25
15-23cm 64 26 30 62 12 22 6 11 8.5 7 8 13 21 101015 18 26 8.5 8 9 10 8 l3
1 lbs/acre = 2‘ppm
lin=2.54 cm
Table A8: Soil P levels at 3 depths and 3 positions relative to tillage for aggressive
tillage with manure
Aggressive tillage with manure soil P concentrations
Block 1 Block 2 Block 3 Block 4
Repetition l 2 l 2 1 2 l 2
position 11213 112I3 11213 11213 11213 112131121311213
ppm
0-7.6cm 116 94 94 141 145 66 51 83 45 22 85 27 90 72 77 125 67 60 86 58 45 95 37 58
7.6-15cm 48 34 36 51 46 43 14 26 10 9.5 13 14 29 37 34 56 39 40 20 18 21 26 19 20
15-23cm 18 ll 15 23 18 20 ll 9 8 5.5 5.5 9 l8 15 20 15 22 22 ll 16 15 21 10 14

 

l lbs/acre = 2*ppm
l in = 2.54 cm

50

 

 

Table A9: Interpolated pre-application soil EC to 30 cm (1 ft) depth by plot number
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
mS/m
7.5 5.7 9.8 8.1 6.6 13.9 15.5 19.5 21.5 20.1 21.2 16.7 17.0 17.9 24.2 25.7
7.1 5.9 10.4 7.5 6.7 13.1 14.9 20.3 20.9 21.3 19.6 15.8 18.5 20.3 22.3 24.7
6.1 6.4 8.1 6.6 6.9 11.4 14.5 19.9 20.4 17.8 18.9 15.6 17.9 18.7 20.9 23.1

 

 

 

uxxnxuxxumnxuxnxnx‘u

I

 

18.7 -21.0
- 21.0 -23.3
- 23.3 -25.7

- No Data

 

 

 

Figure A1: Interpolated Pre-application soil EC (mS/m) to 30 cm (1 ft) depth

51

Table A10: Pre-application soil EC to 91 cm (3 fl) depth (interpolated values) by

 

 

 

plot number
1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16
mS/m
12.6 12.9 17.0 12.2 17.1 20.7 25.5 30.5 36.2 31.7 33.9 28.2 28.6 29.6 31.2 26.6
1 1 6 13.5 15.8 11 1 16.6 21.4 25.2 29.5 36.5 33.1 30.5 27.9 26.6 28.6 28.3 26.4
9 3 12.4 9.4 10 0 16.3 22.2 27.0 28.9 33.8 33.2 26.5 25.8 26.7 28.3 26.4 26.2
8 0 13.4 12 1 10 6 19.5 20.9 29.0 28.4 31.3 30.5 25.2 24.2 24.7 25.2 24.5 25.0
8 2 10.9 11.6 11 2 14.2 20.1 29.8 27.4 29.2 25.7 24.4 23.6 24.9 23.2 22.4 24.3
8 3 9 9 10.4 10 2 18.3 19.0 25.6 26.9 27.1 26.1 25.9 22.4 25.7 19.1 20.9 22.2
7 3 8.8 7.5 9 5 17.6 19.4 25.4 29.7 25.5 25.1 24.1 21.5 26.4 21.3 22.0 21.7
6 9 8.0 6.8 8 1 17.6 19.2 24.9 31.9 24.7 21.9 19.8 20.8 24.7 22.6 23.1 22.8
7 4 8 5 12.2 9 3 16.6 18.4 22.3 28.8 23.2 21.0 18.0 20.1 23.6 22.5 23.4 22.3
8 1 8.5 14.1 8 8 15.4 17.5 19.9 25.0 21.0 20.6 17.9 18.3 22.5 23.0 21.1 19.8
9 7 9.0 9.2 8 0 15.1 17.1 17.9 22.3 19.3 18.3 18.3 17.6 20.7 19.0 20.3 17.9
7 8 8 5 11.7 12 2 8.6 19.3 18.6 19.4 18.4 18.4 19.9 18.6 22.5 17.0 19.6 17.0
7 9 8 7 11.9 13 3 11.9 19.4 17.7 19.9 17.7 19.5 19.4 18.9 20.8 19.3 19.4 17.6
8 4 8 8 13.2 16 0 13.2 19.0 18.8 23.4 17.8 20.8 17.2 20.3 22.9 19.4 19.9 17.8
10 9 9 7 14.7 15 7 14.0 17.5 19.9 22.6 18.2 20.1 23.3 22.8 22.0 19.9 20.0 18.2
13 7 11 0 13.5 16 8 14.7 17.9 20.8 22.1 18.9 19.5 21.3 25.4 25.2 20.9 20.1 18.8
14 0 11 5 13.4 15 1 14.0 17.6 20.9 21.8 20.5 21.1 21.2 24.8 26.8 23.4 20.4 19.0
12 1 12.0 13.8 13 8 15.1 17.6 21.9 24.8 22.6 21.1 22.3 25.8 26.0 26.1 21.7 21.3
12.2 12.2 13.8 13.8 15.7 18.4 23.5 25.5 24.1 21.2 21.5 25.5 24.5 27.3 22.4 22.5

 

 

1:] 6.8 - 10.2
[:3 10.2 - 13.7
13.7 - 17.1

[:3 17.1 -20.6
20.5 -24.0

- 24.0 -27.4
- 27.4 -30.0
- 303 - 34.3
- 34.3 -37.7
- No Data

 

x Extraction points

 

 

 

Figure A2: Interpolated pre-application soil EC (mS/m) to 91 cm (3 fi) depth

52

Table A1 1: 1 day after application interpolated soil EC to 30 cm (1 ft) depth by

 

 

 

plot number
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
mS/m
9 4 10.8 11.4 7 1 10.5 12.9 14.1 20.3 22.1 22.2 28.4 13.4 17.2 14.8 23.6 28.2
91 11 1 14.3 7 7 10.7 11.4 15.6 22.7 20.7 22.2 29.4 13.5 17.2 12.9 23.4 28.4
8 2 11 1 13.8 7 7 10.9 11.4 13.3 20.9 18.3 20.8 25.8 15.9 17.0 14.5 22.4 30.3
7 8 10 4 12.6 6 9 11.1 11.5 12.4 19.0 17.3 20.5 26.6 17.3 17.1 16.3 21.5 29.2
7 7 9 7 12.2 6 2 11.0 9.5 12.3 17.4 16.2 18.2 24.8 16.9 16.5 13.7 20.2 25.4
7 7 9 8 10.5 5 8 11.0 9.8 14.0 18.8 16.1 18.9 23.8 17.2 13.9 16.3 19.7 25.6
7 0 8.6 9.7 6 0 11.2 10.7 14.8 19.6 15.6 18.6 22.3 18.1 14.0 14.7 19.4 23.2
6 7 8.5 9.3 6 9 11.1 9.8 14.4 17.9 13.7 16.5 23.1 18.4 13.0 15.3 19.5 24.8
6 3 7 8 9.5 6 4 10.8 9.6 13.7 17.6 14.3 17.5 21.4 18.6 14.1 12.9 19.4 23.2
5 9 8.1 10.1 6 4 10.9 9.9 14.0 17.0 14.2 17.0 21.2 18.0 14.7 12.2 18.2 20.4
6 2 8.6 11.1 6 5 10.4 10.1 13.2 17.7 14.5 17.4 19.5 16.7 13.1 10.6 17.5 19.5
6 8 8 7 10.2 5 7 9.6 10.2 12.3 16.5 14.8 18.1 19.4 17.0 14.4 10.5 17.6 18.8
6 8 9 3 10.6 6 7 9.8 10.4 12.4 16.8 15.0 17.4 20.8 17.1 13.1 10.5 16.9 18.8
7 1 10 1 12.0 7 8 10.7 10.5 14.4 16.5 14.6 16.0 20.1 18.8 12.6 11.0 18.4 19.4
72 11.1 11.6 93 11.1 10.5 14.4 16.8 14.1 16.6 20.6 18.1 11.9 11.3 19.8 20.6
7 4 10.5 11.8 10 3 10.7 10.2 14.6 16.8 14.0 16.5 20.1 18.7 11.3 11.6 19.9 18.1
8 5 11.0 12.4 10.4 10.7 10.6 16.4 16.4 14.8 15.6 20.9 19.0 11.7 12.4 20.6 20.1
8 3 11.4 12.9 10.4 10.7 11.7 15.1 16.3 15.1 15.8 22.6 18.5 12.3 13.3 24.4 18.7
8 5 11.1 12.8 11.1 10.7 11.3 13.8 16.2 16.1 13.3 21.9 17.6 10.7 11.7 20.8 19.8

 

 

[:1 6.7 -0.4

1:] 3.4 - 11.2

112 - 13.9
13.9 - 16.6

[:1 16.6 - 19.4
19.4 -22.1

— 22.1 -24.9
- 24.9 -27.6
- 27.0 -30.3
- No Data

 

x Extraction points

 

 

Figure A3: 1 day after application interpolated soil EC(mS/m) to 30 cm (1 fl) depth

53

 

Table A12: 1 day after application interpolated soil EC to 91 cm (3 fi) depth by

 

 

 

plot number
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
mS/m
11.6 14.2 17.4 15.7 14.8 20.2 24.0 29.2 36.0 32.1 31.4 31.0 26.5 30.8 30.6 26.5
12.0 13.7 16.9 14.5 14.4 20.0 23.8 28.3 37.4 30.7 29.9 29.1 27.0 30.6 29.8 26.2
10.2 13.7 16.3 12.4 14.6 18.4 27.2 27.0 33.4 31.0 27.2 27.2 25.2 29.9 27.3 26.4
8.4 14.6 14.4 1 1.6 15.0 18.6 26.8 26.0 30.7 29.9 25.8 25.0 25.3 27.6 26.0 25.7
7.7 13.4 14.1 10.8 13.8 18.8 23.9 24.5 28.2 27.5 24.8 23.7 26.3 25.5 24.4 25.0
8.6 14.0 12.7 11.0 14.6 16.5 23.9 25.4 25.9 25.7 24.1 23.3 23.8 21.5 22.4 23.4
8.1 10.8 11.1 10.3 14.5 17.3 23.1 26.4 24.7 25.3 22.3 22.4 24.7 19.7 21.3 22.7
7.5 10.7 10.2 10.4 13.5 17.0 21.7 25.7 23.5 22.2 19.3 21.1 24.7 21.1 22.1 22.5
7.5 8.8 8.8 9.5 13.1 16.5 20.5 23.9 23.0 22.3 17.5 20.6 23.1 20.6 22.8 23.8
8.0 9.3 9.8 9.8 13.5 15.7 l8.7 22.1 20.8 21.5 16.9 19.5 23.7 21.6 22.1 21.9
8.8 9.8 13.2 9.7 12.9 17.7 18.2 21.4 19.4 19.6 17.3 18.6 24.2 21.0 19.9 18.7
8.1 9.4 11.3 9.5 12.8 18.3 18.8 21.0 17.9 19.2 18.6 18.7 23.8 18.9 19.4 17.8
7.8 9.9 12.7 11.5 13.0 17.3 18.8 22.0 17.7 19.5 l8.9 19.1 21.8 19.4 18.3 17.5
8.2 9.9 12.2 12.1 12.9 16.8 19.7 22.3 18.3 19.3 16.6 20.0 21.6 19.5 18.9 18.1
9.0 10.2 12.7 12.6 13.1 16.1 20.1 22.3 18.7 20.1 17.7 21.2 22.3 20.9 19.4 18.4
11.4 11.5 13.4 14.3 13.2 16.4 19.9 21.9 18.8 19.6 19.8 22.3 21.1 20.7 20.1 18.9
12.9 12.4 14.8 15.0 13.2 16.7 20.9 23.2 19.5 19.9 20.4 23.4 22.9 21.1 20.3 19.1
12.2 11.9 12.6 14.6 13.2 18.1 24.4 24.3 20.6 20.5 21.4 23.1 25.9 24.4 22.9 19.4
12.0 12.2 15.1 13.0 13.3 l8.4 25.7 24.3 22.2 20.8 21.5 24.0 25.1 26.1 22.4 21.3

 

 

[:1 7.404 - 10.7..
[:1 10.707 - 14.111

14.111 - 17.434
17.434 - 20.750

20.750 - 24.001
- 24.001 - 27.405
- 27.405 - 30.720
- 30.720 - 34.052
- 34.052 - 37.375
- No om

 

11 Extraction points

 

 

 

Figure A4: 1 day afier application interpolated soil EC (mS/m) to 91 cm (3 ft) depth

54

Table A13:

1 week after application interpolated soil EC to 30 cm (1 fi) depth by

 

 

 

plot number
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
mS/m
10.1 12.7 17.5 17.4 13.4 14.3 19.4 25.3 23.8 29.0 33.0 22.4 21.7 19.7 23.5 27.8
10.6 12.2 19.1 16.5 13.7 14.7 18.7 23.4 21.9 28.8 29.2 21.2 21.6 22.3 23.3 27.8
9.8 12.0 18.4 13.6 14.0 13.6 19.1 21.7 22.7 25.1 27.8 18.8 19.6 19.2 23.7 28.0
9.5 13.2 17.3 14.6 13.7 12.4 19.1 19.8 22.4 25.3 27.3 19.5 18.8 19.4 24.3 26.4
9.8 11.8 14.0 11.5 12.8 12.4 16.4 18.9 20.7 24.1 26.3 19.5 18.8 19.9 24.7 26.0
9.0 10.0 11.4 10.2 12.1 12.6 13.8 20.1 19.9 24.5 27.2 20.6 18.7 18.1 22.5 22.6
8.4 9.7 11.6 9.4 12.5 13.1 13.5 19.5 20.0 22.6 26.0 19.0 16.6 |8.5 21.5 21.9
8.0 9.7 12.7 10.0 12.4 12.3 13.7 18.3 20.2 22.8 26.6 20.0 18.1 18.4 21.6 21.8
8.2 10.5 13.8 11.3 12.4 12.3 12.5 17.5 20.7 22.3 25.3 19.9 17.8 17.0 22.0 21.2
8.6 9.8 13.5 10.7 12.2 13.2 13.5 17.0 21.2 22.5 25.2 20.4 16.6 16.1 22.3 22.1
8.3 9.5 13.4 9.6 11.6 13.4 15.9 17.2 21.3 22.3 24.9 20.7 17.0 14.8 23.1 22.2
8.7 11.1 13.6 11.1 11.7 12.6 14.6 17.7 21.2 21.8 24.8 22.8 16.4 15.5 24.1 21.9
9 1 10.8 14.3 13.8 13.0 12.6 16.6 17.1 20.3 21.3 23.3 23.1 15.7 16.0 25.0 21.5
9 1 11.6 13.8 14.6 13.9 12.7 17.5 16.7 20.4 21.4 23.1 21.0 15.6 16.7 30.0 21.8
9.7 12.3 16.3 15.3 13.2 12.5 l8.5 16.8 20.6 19.7 23.7 21.5 15.0 16.6 45.8 19.9
10.3 13.0 15.5 14.4 12.5 13.5 19.8 17.2 20.1 19.1 25.5 20.5 15.8 15.6 36.5 23.0
10.0 13.7 14.4 13.5 12.9 13.8 19.2 18.7 21.3 19.3 26.9 20.1 14.9 16.6 31.1 24.8
9.9 14.0 15.0 12.4 12.7 13.3 22.7 19.5 23.3 20.1 28.5 21.7 15.8 20.1 30.9 32.7
10.9 14.4 14.9 12.9 13.1 14.8 21.5 19.6 23.6 20.7 27.6 24.9 16.1 21.3 31.5 31.4

 

 

HkHKHXHHnHHKHHHNHb-(k

X

Extraction points

1:] 0.0 - 12.2
11:] 12.2 -10.4
10.4 - 20.5

- No Data

 

    

 

 

Figure A5: 1 week after application interpolated soil EC(mS/m) to 30 cm (1 fl) depth

55

Table A14: 1 week after application interpolated soil EC to 91 cm (3 fl) depth by

 

 

 

plot number
1 2 3 4 5 6 7 8 9 10 l l 12 13 14 15 16
mS/m
15 4 13.6 16 8 13 6 15.9 20.0 26.3 37.1 27.2 32.8 33.7 26.4 26.5 23.2 24.4 23.1
13 4 12.9 17 7 12 4 16.9 18.1 25.3 34.8 25.3 32.3 30.7 25.9 26.9 21.3 22.7 22.9
10 6 13.4 15.5 11 4 15.7 17.9 25.5 32.6 26.0 30.9 29.1 23.8 26.1 19.7 22.6 23.6
9 5 13 5 14.8 12 8 15.2 17.0 25.3 30.0 27.2 29.2 28.0 22.4 25.7 21.7 24.2 24.1
9 6 12 6 12.9 11 4 16.3 18.4 23.7 27.9 27.0 27.1 28.0 22.5 25.1 22.3 24.8 24.7
9 1 11 7 11.6 10 7 15.8 18.8 21.5 26.9 24.8 27.7 26.0 21.7 24.1 23.5 22.6 22.1
8 2 10.5 10.4 9 9 14.5 18.3 19.1 25.2 23.6 23.5 23.3 20.5 23.5 21.7 21.1 19.9
8 3 9.7 11.1 10 0 14.2 18.1 17.8 24.8 23.1 22.4 21.2 19.8 24.8 19.1 20.9 18.6
8 5 10 7 13.7 10 2 15.2 19.6 18.2 23.1 22.1 21.6 20.8 19.0 23.6 18.9 20.2 19.3
9 7 9 8 13.0 9 8 14.3 21.7 18.9 21.4 23.1 20.4 21.0 19.4 22.8 20.6 21.1 19.8
9 2 10.2 12.2 12 2 13.5 20.0 19.9 21.0 23.2 19.6 22.0 19.5 21.3 20.1 22.4 20.6
8 6 10.5 14.1 13 1 13.1 19.4 21.5 20.4 23.0 21.2 22.1 20.5 22.6 19.9 22.9 20.0
9 0 10 4 13.4 13 4 14.0 18.1 21.4 19.9 22.9 20.5 20.0 21.6 23.5 20.7 23.1 20.9
10 0 11.3 13.9 15 7 14.8 18.4 21.7 19.3 24.1 21.1 23.4 23.4 25.9 22.7 26.1 21.1
12 0 12.5 16 1 15 9 15.1 18.5 23.6 20.3 25.4 19.6 23.1 25.0 26.0 24.8 31.9 23.1
13 9 14.0 14.0 15 2 14.7 19.9 26.5 21.3 26.0 20.1 24.1 24.1 26.4 26.5 30.7 24.7
13 4 l3 5 14.7 13 6 15.1 20.7 27.9 22.9 27.1 21.4 24.5 23.9 24.9 28.9 29.8 28.4
12 7 14.6 16.0 12 7 16.1 19.7 27.9 24.4 28.8 21.9 25.2 25.8 25.5 30.0 30.8 33.5
13 5 13.3 15 5 13 5 16.4 20.4 27.5 26.1 29.1 22.2 25.0 26.4 25.7 30.0 31.6 33.8

 

 

“a“...amkmxmwul

xnnnnnixxnxxxxxxxuu

[:1 02 - 11.4

:1 11.4 - 14.0
14.5 -17.0
El 17.0 -21.0
CI 21.0 -24.2
- 242 -27.4
- 27.4 .300
- 30.0 -33.0
- 33.0 -370

- No Data

 

r Extraction points

    

 

 

Figure A6: 1 week afier application interpolated soil EC (mS/m) to 91 cm (3 fl) depth

56

Table A15: OM, P, and K of multiple depth soil cores taken at flags

 

 

 

 

 

 

 

Flag OM P K
0-15 cm 15-300m 30-61 cm 61-91 cm 0-15 cm 15-300m 30-61 cm61-9l cm 0-15 cm 15-30cm 30-61 cm 61-91 cm
% ppm

W1 4.2 3.4 1.6 1.3 39 21 6 6 174 77 61 69
W2 4.4 3.6 1.2 1.1 30 21 9 11 161 72 61 49
W3 4.5 3.5 1.3 1.4 40 22 8 9 203 97 63 43
W4 3.6 3.5 0.6 1.2 15 9 2 3 122 77 43 38
W5 4.4 4.5 1.8 l 25 14 10 9 137 68 61 40
W6 3.8 4.2 1.1 1.6 17 ll 4 4 112 53 52 55
W7 3.8 2.7 1.3 1.2 14 5 4 3 91 59 43 33
W8 3.7 3.4 0.9 2 24 10 3 4 165 74 55 62
01 3.5 2 0.9 NS 24 10 5 NS 183 85 58 NS
02 4 4.3 0.8 0.7 30 18 7 8 219 91 71 70
O3 4 2 0.8 0.8 26 6 3 2 157 74 6O 46
P1 2.6 2.8 l 1.5 39 28 2 3 189 117 63 66
P2 2.8 2.3 0.8 1 54 17 10 4 209 62 37 32
P3 2.7 2.7 1 1.4 3O 19 5 3 169 95 51 51
Yl 5.3 4.7 1.5 1.1 16 11 3 1 137 79 92 45
Y2 4.9 4 1.1 1.6 15 10 3 5 99 74 53 86
Y3 3.7 2.5 1.4 1.5 12 2 2 7 111 70 68 40

 

Table A16: Mg, Ca, and pH of multiple depth soil cores taken at flags

 

 

 

 

 

 

 

Flag Mg Ca Acidity
-15 cm 15-300m 30-61 cm 61-91 cm 0-15 cm 15-30cm 30-61 cm 61-91 cm 0-15 cm 15-300m 30-61 cm 61-91 cm
ppm ph
WI 270 245 255 265 1700 1650 1450 1250 6.3 6 7 7.3

W2 240 235 240 185 1300 1500 1350 850 5.9 5.9 6.8 7.8
W3 270 260 240 170 1450 1550 1200 900 6.2 6.1 7.1 7.8
W4 345 370 255 245 1600 1700 3100 2950 6.6 6.8 8.2 8.2
W5 315 375 305 180 1850 2300 1750 800 6.5 6.9 7.3 7.8
W6 325 285 230 235 1750 1700 115 1050 6.7 6.9 7.3 7.5
W7 275 340 270 235 1500 1650 1650 2100 6.5 7.1 7.6 8.1
W8 360 365 345 380 1650 1600 1400 1800 7.1 7.3 7.7 7.52
01 335 325 270 NS 1550 1450 950 NS 6.8 7.3 7.6 NS
02 335 400 190 210 1550 2100 800 900 6.7 6.9 6.8 7.2
03 320 310 265 210 1550 1350 2500 4300 6.8 7.1 8 8.3
P1 135 110 225 300 650 600 1050 1100 5.8 5.6 6.5 3.9
P2 155 110 90 110 800 650 500 550 6.2 6.1 6.7 7.1

P3 135 130 145 260 750 850 750 2400 5.9 6 6.9 8
Y1 380 430 500 255 2150 2300 2000 3900 6.8 6.9 7.5 8.4
Y2 365 335 330 445 2200 1700 3400 1750 6.8 7 7.9 7.7

Y3 330 400 360 260 16001700 1550 3200 7.2 7.5 7.8 8.1

 

57

Table A17: Clay, sand and silt of multiple depth soil cores taken at flags

 

Flag Clay Sand Silt
0-15 cm 15-300m 30-61 cm 61-91 cm 0-15 cm 15-30cm 30-61 cm 61-91 cm 0-15 cm 15-30cm 30-61 cm 61-91 cm

 

 

 

 

%

 

W1 21 21 23 23 50 52 58 52 29 27 19 25
W2 23 21 19 17 58 50 54 58 19 29 27 25
W3 19 22 18 22 52 54 6O 68 29 24 22 10
W4 24 26 18 24 50 46 54 56 26 28 28 20
W5 22 24 22 12 46 48 56 68 32 28 22 20
W6 20 20 22 22 46 48 50 52 34 32 28 26
W7 20 24 18 18 48 50 5 6 60 32 26 26 22
W8 22 22 20 NS 50 49 59 NS 28 29 21 NS
01 19 17 13 NS 50 60 64 NS 31 23 23 NS
02 21 17 15 17 48 47 62 58 31 36 23 25
O3 19 17 15 17 48 54 56 54 33 29 29 29
P1 14 14 22 20 57 57 49 69 29 29 29 11
P2 12 14 14 10 57 51 61 71 31 35 25 19
P3 12 12 12 16 57 57 61 57 31 31 27 27
Y1 22 35 32 22 47 1.5 29 43 31 37 39 35
Y2 24 22 21 26 43 49 49 39 33 29 30 35
Y3 17 25 24 18 51 49 49 45 32 26 27 37

 

Table A18: CBC and EC of multiple depth soil cores taken at flags

 

 

 

 

CEC (meq/ 100g) EC (mS/m)

Flag 015 cm 15-30 cm 30-61 cm 61-91 cm 030 cm 091 cm
W1 13.6 14.1 9.5 8.6 11.3 26.5
W2 12.5 13.2 9.2 5.9 11.6 15.9
W3 12.4 12.6 8.2 6 14.3 20.5
W4 12.4 12.1 16.9 16.9 16.6 18.8
W5 13.4 15 11.4 5.6 13.3 18.1
W6 12.9 11.2 7.8 7.3 12.8 19

W7 11.2 11.2 10.6 12.5 13.5 22.1
W8 11.7 11.2 10 12.3 13.8 19.4
01 11.4 10.2 7.1 NS 14.8 18.2
02 12.3 14.3 5.9 6.4 15.9 19.7
03 11.2 9.5 14.9 23.4 15.9 19.7
P1 6.1 6.6 8.5 8.3 5.2 9.9

P2 7 5.5 3.3 3.7 8.4 14.5

P3 6.5 6.8 5.2 14.3 4.8 7.6

Y1 14.7 15.5 14.4 21.7 21.5 32.4
Y2 14.7 11.5 19.9 12.7 17.4 26.7
Y3 ll 12 10.9 18.3 14.4 29.3

 

58

Table A19: Soil bulk density at fLags before slurry application (15 August 2002)

 

 

 

 

 

 

Flag BD Sample 1 BD Sample 2 BD Sample 3
0-8 cm 8-15cm 15-23 23-300m 0-8 cm 8-15cm 15-23 23-300m 0-8 cm 8-150m 15-23 23-30cm
g/cm3

WI 1.32 1.44 1.42 1.72 1.43 1.42 1.51 1.52 1.28 1.36 1.62 1.52
W2 1.40 1.41 1.37 1.37 1.30 1.42 1.42 1.48 1.31 1.49 1.33 1.48
W3 1.36 1.44 1.48 1.60 1.31 1.32 1.40 1.59 1.34 1.34 1.42 1.59
W4 1.42 1.41 1.36 1.45 1.25 1.37 1.38 1.55 1.49 1.36 1.38 1.55
W5 1.37 1.34 1.37 1.46 1.68 1.39 1.42 1.17 1.26 1.26 1.26 1.17
W6 1.31 1.46 1.33 1.54 1.37 1.48 1.36 1.31 1.32 1.44 1.41 1.31
W7 1.44 1.48 1.38 1.43 1.34 1.46 1.50 1.43 1.35 1.31 1.43 1.43
W8 1.41 1.46 1.37 1.47 1.36 1.45 1.48 1.61 1.50 1.46 1.50 1.61
01 1.50 1.51 1.33 1.61 1.38 1.44 1.57 1.56 1.36 1.36 1.57 1.56
02 1.40 1.37 1.44 1.37 1.38 1.56 1.45 1.62 1.39 1.42 1.50 1.62
03 1.28 1.53 1.31 1.53 1.24 1.54 1.46 1.55 1.27 1.44 1.37 1.55
Pl 1.48 1.36 1.46 1.43 1.42 1.45 1.46 1.34 1.44 1.42 1.55 1.34
P2 1.35 1.81 1.42 1.55 1.39 1.09 1.50 1.46 1.41 1.43 1.42 1.46
P3 1.48 1.36 1.46 1.43 1.42 1.45 1.46 1.34 1.44 1.42 1.55 1.34
Y1 1.33 1.33 1.30 1.56 1.27 1.36 1.44 1.32 1.37 1.45 1.32 1.32
Y2 1.36 1.49 1.33 1.51 1.42 1.43 1.45 1.36 1.42 1.43 1.35 1.36
Y3 1.46 1.40 1.40 1.56 1.44 1.50 1.48 1.44 1.44 1.42 1.40 1.44

 

l oflin3 = 1.73 g/cm3
1 in = 2.54 cm

Table A20: Gravimetric water content at flags before application (14 August 2002)

 

 

 

 

Flag Gravimetric Water Content
0-15 cm 15-30 cm 30—61 cm 61-91 cm
8/8

W1 0.16 0.16 0.18 0.20
W2 0.13 0.19 0.16 0.17
W3 0.11 0.19 0.17 0.18
W4 0.18 0.21 0.15 0.18
W5 0.15 0.22 0.20 0.16
W6 0.17 0.21 0.16 0.17
W7 0.17 0.20 0.18 0.16
W8 0.15 0.18 0.21 0.16
01 0.19 0.21 0.14 0.00
02 0.18 0.26 0.20 0.18
03 0.18 0.13 0.15 0.14
P1 0.12 0.15 0.13 0.15
P2 0.11 0.14 0.12 0.13
P3 0.12 0.14 0.10 0.15
Y1 0.18 0.22 0.21 0.15
Y2 0.15 0.17 0.16 0.25
Y3 0.14 0.17 0.21 0.17

 

59

Table A21: Gravimetric water content (g/g) at flags after application (26 August 2002)

 

 

F_lag Sample 1 Sample 2
W1 0.30 0.25
W2 0.28 0.26
W3 0.28 0.29
W4 NS 0.27
W5 0.30 0.28
W6 0.30 0.29
W7 0.27 0.30
W8 0.24 0.27
01 NS NS
02 NS NS
03 NS 0.27
P1 0.22 0.23
P2 0.22 0.24
P3 0.24 0.27
Y1 0.31 0.32
Y2 0.28 0.28
Y3 0.27 0.26

 

60

APPENDIX B

Table Bl: Ten minute infiltration rate AN OVA

 

 

 

 

 

 

 

 

Source DF Sum of Squares Mean Squares F -value Pr> F
Total 23 SS total

A 2 333.0173 166.509 9.83 0.0128
B 3 1.624 0.541 0

B*A 6 101.681 16.947 0.42 0.8464
B*C 4 46.895 11.724 0.29 0.8759
Error 8 322.348 40.297

A=Ti11age

B=Block

C=North or South subsample

DF= Degrees of freedom

Table 82: Residue cover ANOVA

Source DF Sum of Squares Mean Squares F-value Pr> F
Tillage 2 0.030123 0.015061 5.62 0.0688
Block 3 0.027056 0.009019 3.37

Error 4 0.010710 0.002678

Table B3: Surface manure coverage ANOVA

Source DF Sum of Squares Mean Squares F-value Pr> F
Tillage 1 81.92 81.92 3.21 0.1710
Block 3 52.77 17.59 0.69 0.6162
Error 3 76.51 25.50

 

Table B4: ANOVA table for bulk density as a function of treatment and depth

 

 

Effect Numerator Denominator F-value Pr> F
degrees of degrees of
freedom freedom
Tillage l 3 5.05 0.1 101
Depth 2 28 41.59 <0.0001
Tillage*depth 2 28 5.28 0.0113

 

61

Table B5: Phosphorous application uniformity ANOVA

 

 

Effect Num. df Den. df F -value Pr>F

Treatment 3 1 1.8 2.47 0.1 127
Position 2 29.5 2.48 0.1007
Treatrnent*Position 6 29.5 0.93 0.4865
Depth 2 84 195.49 <.0001
Trt*Depth 6 84 13.25 <.0001
Position*depth 4 84 2.79 0.03 l 6
Trt*position*Depth 12 84 1.62 0.1003

 

Table B6: Analysis of covariance table for phosphorus concentration as a function of
treatment and tine position with soil EC as a covariate separately at each depth.

 

Effect Num. Den

F-value (Level of significance shown in

 

 

df df parenthesis)
O-7.6 cm (03 in) 7.6-15 cm (3-6 in) 15-23 cm (6-9 in)

AIC= 714.9 749.2 705.7
Treatment 3 5 12.1(0.010) 1.88(0.25) 0.64(0.62)
Position 2 24 5.0 (0.015) 0.04(0.96) 0.55(0.58)
Treatrnent*Position 6 24 1.4 (0.265) 0.96(0.48) 2.34(0.065)
EC 1 5 26.4 (0.004) 9.4(0.028) 7.53(0.041)
Treatrnent*EC 3 24 7.0 (0.002) NS NS

 

Table B7: AN OVA table for phosphorus concentration as a function of treatment and tine

position separately at each depth.

 

 

 

 

Eflect Numerator Denominator F-value Level of
degrees of degrees of significance
freedom freedom

Depthl AIC=743.1

Treatment 3 9 5.8 0.018

Position 2 24 4.7 0.019

Treatrnent*Position 6 24 1 .3 0.300

Depth2 AIC= 758.4

Treatment 3 9 0.40 0.76

Position 2 23 0.05 0.95

Treatment*Position 6 23 0.97 0.46

Depth3 AIC=712.6

Treatment 3 9 0.34 0.79

Position 2 23 0.52 0.60

Treatment*Position 6 23 2.35 0.65

 

62

Table BS: Pre-application soil EC at 91 cm (3 fi) depth ANOVA

 

Significance
Source DF Sum of Squares Mean Square F-value p-value
Trt 3 515.82 171.94 1.79 0.2194
Blck 3 7535.99 2512.00 26.12 <.0001
Blck*trt 9 865.58 96.18 7.99 <.0001

Error 288 3468.55 12.04

 

Table B9: 1 day after application soil EC at 91 cm (3 ft) depth ANOVA

 

 

Significance
Source DF Sum of Squares Mean Square F-value p-value
Trt 3 595.39 198.46 1.91 0.1990
Blck 3 6597.73 2199.24 21.13 0.0002
Blck*trt 9 936.82 104.09 9.99 <.0001

Error 288 3001.49 10.42

 

Table B10: 1 week after application soil EC at 91 cm (3 ft) depth ANOVA

 

 

 

 

 

Significance
Source DF Sum of Squares Mean Square F-value p-value
Trt 3 408.48 136.16 1.25 0.3448
Blck 3 6993.55 2331.18 21.59 0.0002
Blck*trt 9 971.80 107.98 11.49 <.0001
Error 288 2705.43 9.39
Table Bl 1: Pre-application soil EC at 30 cm depth (1 ft) ANOVA

Significance
Source DF Sum of Squares Mean Square F-value p-value
Trt 3 238.75 79.58 0.97 0.4490
Blck 3 4090.80 1363.60 16.6 0.0005
Blck‘trt 9 739.44 82.16 17.13 <.0001

Error 288 1381.28 4.80

 

Table B12: 1 day after application soil EC at 30 cm depth (1 11) AN OVA

 

 

Significance
Source DF Sum of Squares Mean guiare F-value p—value
Trt 3 1389.66 463.22 32.0 0.0764
Blck 3 4149.15 1383.05 9.56 0.0037
Blck*trt 9 1301.50 144.61 36.11 <.0001

Error 288 1153.35 4.00

 

63

Table B13: 1 week after application soil EC at 30 cm depth (1 ft) ANOVA

 

 

Significance
Source DF Sum of Squares Mean Square F-value p-value
Trt 3 1254.97 418.32 3.25 0.0742
Blck 3 5874.37 1958.12 15.2 0.0007
Blck*trt 9 1159.41 128.82 19.21 <.0001

Error 288 1930.90 6.7

64

APPENDIX C

Figure C1: Shatter tine helical mount configuration for two sets of shatter tines
courtesy of Aerway”)

 

 

 

 

 

Figure C2: Rear and side views of rolling tine harrow (courtesy of AerwayTM)

 

NOTE: TINES ARE ANGLED TOWARDS
THE OUTSiDE BRACKETS

[—

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

'7

l J . ROTANON .
I“
A + 1/a + 1/4 A

 

 

 

65

Figure C3: Top and side of 10 foot rolling tine harrow. (courtesy of AerwayTM)

 

(

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

66

Figure C5: AerwayTM in use on experimental plots

 

1
l

.' .1 ‘
0 - ' ' "4343;134:3035
. .1 |‘ ‘ IA «49'3;;> 4‘
.. 1.2181" 1“? 441'
a“ '.v , 11",-.V ' .'I . 4. "I
:1“ : I» l“ '1‘M1.:l1rig F"\5}fi4 ‘ ‘ ".oi'lrLfi
3 _, ,..-..,..,_,..~,, .2 - .. :28. 1,

2.091

 

 

 

 

67

S’MAD

 

 

 

68

calibrated
£13an15 7

1 1 1
outeriing depth {range ‘

inner ring
,1"—

 

 

 

 

69

 

Figure C12: AerwayTM light tillage void cavities (excavation normal to travel)
. f

) _
1710 1‘9‘2‘0 2122 23 2'4 .
"’a'fl NI'NUSD‘
u: “1‘ . 5131 1'12 ‘15 ~ 1'13 51. 1'15:
‘ f.

111

 

70

Figure C14: AerwayTM aggressive tillage void cavities, top view (excavation normal to
travel

 

71

AerwayTM light tillage void cav

C16

Figure

ity pattern

H

1‘-

', .‘ " .2'.

.3.

 

AerwayTM aggressive tillage void cavity pattern

Figure C17:

 

72

Figure C18: AerwayTM aggressive tillage 3-D void cavities model

 

 

0 2 4 6 8 101214lnches
E

 

 

 

Fi 6 C19: AerwayTM light tillage 3-D void cavities model

 

 

0 2 4 6 8 1012|nches
=22:

 

 

 

 

73

 

F11 re C20: Aerwa TM no tilla_e surface manure covera c with tire track

"‘ .‘/ .311». "
._, p . .

A 811i”

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